matlab - Different results between a mex file and C file -

i have matlab code in computationally expensive part converted c mex file. mex file is:

/* copyright henrik stewenius*/  /*************************************************   indata  : 9x4 matrix    data out: 10x20 matrix    *************************************************/ #include "mex.h" #include <math.h>   void mexfunction(int nlhs, mxarray *plhs[],                  int nrhs, const mxarray *prhs[]) /*nlhs    number of expected mxarrays.   plhs    pointer array of null pointers.   nrhs    number of input mxarrays.   prhs    pointer array of input mxarrays.    */ {   double *ee, *a;   double e00,e01,e02,e03,e04,e05,e06,e07,e08;   double e10,e11,e12,e13,e14,e15,e16,e17,e18;   double e20,e21,e22,e23,e24,e25,e26,e27,e28;   double e30,e31,e32,e33,e34,e35,e36,e37,e38;    double e002,e012,e022,e032,e042,e052,e062,e072,e082;   double e102,e112,e122,e132,e142,e152,e162,e172,e182;   double e202,e212,e222,e232,e242,e252,e262,e272,e282;   double e302,e312,e322,e332,e342,e352,e362,e372,e382;    double e003,e013,e023,e033,e043,e053,e063,e073,e083;   double e103,e113,e123,e133,e143,e153,e163,e173,e183;   double e203,e213,e223,e233,e243,e253,e263,e273,e283;   double e303,e313,e323,e333,e343,e353,e363,e373,e383;    if(nrhs != 1  )     mexerrmsgtxt("ee (10*4)\n");   ee = mxgetpr( prhs[0] )  ;   plhs[0] = mxcreatedoublematrix(10 ,20  , mxreal);    = mxgetpr( plhs[0]);   e00 = ee[0*9 + 0 ]; e10 = ee[1*9 + 0 ]; e20 = ee[2*9 + 0 ]; e30 = ee[3*9 + 0 ]; e01 = ee[0*9 + 1 ]; e11 = ee[1*9 + 1 ]; e21 = ee[2*9 + 1 ]; e31 = ee[3*9 + 1 ]; e02 = ee[0*9 + 2 ]; e12 = ee[1*9 + 2 ]; e22 = ee[2*9 + 2 ]; e32 = ee[3*9 + 2 ]; e03 = ee[0*9 + 3 ]; e13 = ee[1*9 + 3 ]; e23 = ee[2*9 + 3 ]; e33 = ee[3*9 + 3 ]; e04 = ee[0*9 + 4 ]; e14 = ee[1*9 + 4 ]; e24 = ee[2*9 + 4 ]; e34 = ee[3*9 + 4 ]; e05 = ee[0*9 + 5 ]; e15 = ee[1*9 + 5 ]; e25 = ee[2*9 + 5 ]; e35 = ee[3*9 + 5 ]; e06 = ee[0*9 + 6 ]; e16 = ee[1*9 + 6 ]; e26 = ee[2*9 + 6 ]; e36 = ee[3*9 + 6 ]; e07 = ee[0*9 + 7 ]; e17 = ee[1*9 + 7 ]; e27 = ee[2*9 + 7 ]; e37 = ee[3*9 + 7 ]; e08 = ee[0*9 + 8 ]; e18 = ee[1*9 + 8 ]; e28 = ee[2*9 + 8 ]; e38 = ee[3*9 + 8 ];   e002 =e00*e00; e102 =e10*e10; e202 =e20*e20; e302 =e30*e30; e012 =e01*e01; e112 =e11*e11; e212 =e21*e21; e312 =e31*e31; e022 =e02*e02; e122 =e12*e12; e222 =e22*e22; e322 =e32*e32; e032 =e03*e03; e132 =e13*e13; e232 =e23*e23; e332 =e33*e33; e042 =e04*e04; e142 =e14*e14; e242 =e24*e24; e342 =e34*e34; e052 =e05*e05; e152 =e15*e15; e252 =e25*e25; e352 =e35*e35; e062 =e06*e06; e162 =e16*e16; e262 =e26*e26; e362 =e36*e36; e072 =e07*e07; e172 =e17*e17; e272 =e27*e27; e372 =e37*e37; e082 =e08*e08; e182 =e18*e18; e282 =e28*e28; e382 =e38*e38;  e003 =e00*e00*e00; e103 =e10*e10*e10; e203 =e20*e20*e20; e303 =e30*e30*e30; e013 =e01*e01*e01; e113 =e11*e11*e11; e213 =e21*e21*e21; e313 =e31*e31*e31; e023 =e02*e02*e02; e123 =e12*e12*e12; e223 =e22*e22*e22; e323 =e32*e32*e32; e033 =e03*e03*e03; e133 =e13*e13*e13; e233 =e23*e23*e23; e333 =e33*e33*e33; e043 =e04*e04*e04; e143 =e14*e14*e14; e243 =e24*e24*e24; e343 =e34*e34*e34; e053 =e05*e05*e05; e153 =e15*e15*e15; e253 =e25*e25*e25; e353 =e35*e35*e35; e063 =e06*e06*e06; e163 =e16*e16*e16; e263 =e26*e26*e26; e363 =e36*e36*e36; e073 =e07*e07*e07; e173 =e17*e17*e17; e273 =e27*e27*e27; e373 =e37*e37*e37; e083 =e08*e08*e08; e183 =e18*e18*e18; e283 =e28*e28*e28; e383 =e38*e38*e38;   a[0 + 10*0]=0.5*e003+0.5*e00*e012+0.5*e00*e022+0.5*e00*e032+e03*e01*e04+e03*e02*e05+0.5*e00*e062+e06*e01*e07+e06*e02*e08-0.5*e00*e042-0.5*e00*e052-0.5*e00*e072-0.5*e00*e082; a[0 + 10*1]=e00*e11*e01+e00*e12*e02+e03*e00*e13+e03*e11*e04+e03*e01*e14+e03*e12*e05+e03*e02*e15+e13*e01*e04+e13*e02*e05+e06*e00*e16+1.5*e10*e002+0.5*e10*e012+0.5*e10*e022+0.5*e10*e062-0.5*e10*e042-0.5*e10*e052-0.5*e10*e072+0.5*e10*e032+e06*e11*e07+e06*e01*e17+e06*e12*e08+e06*e02*e18+e16*e01*e07+e16*e02*e08-e00*e14*e04-e00*e17*e07-e00*e15*e05-e00*e18*e08-0.5*e10*e082; a[0 + 10*2]=e16*e02*e18+e03*e12*e15+e10*e11*e01+e10*e12*e02+e03*e10*e13+e03*e11*e14+e13*e11*e04+e13*e01*e14+e13*e12*e05+e13*e02*e15+e06*e10*e16+e06*e12*e18+e06*e11*e17+e16*e11*e07+e16*e01*e17+e16*e12*e08-e10*e14*e04-e10*e17*e07-e10*e15*e05-e10*e18*e08+1.5*e00*e102+0.5*e00*e122+0.5*e00*e112+0.5*e00*e132+0.5*e00*e162-0.5*e00*e152-0.5*e00*e172-0.5*e00*e182-0.5*e00*e142; a[0 + 10*3]=0.5*e103+0.5*e10*e122+0.5*e10*e112+0.5*e10*e132+e13*e12*e15+e13*e11*e14+0.5*e10*e162+e16*e12*e18+e16*e11*e17-0.5*e10*e152-0.5*e10*e172-0.5*e10*e182-0.5*e10*e142; a[0 + 10*4]=-e00*e28*e08-e00*e25*e05-e00*e27*e07-e00*e24*e04+e26*e02*e08+e26*e01*e07+e06*e02*e28+e06*e22*e08+e06*e01*e27+e06*e21*e07+e23*e02*e05+e23*e01*e04+e03*e02*e25+e03*e22*e05+e03*e01*e24+e03*e21*e04+e00*e22*e02+e00*e21*e01-0.5*e20*e082-0.5*e20*e052-0.5*e20*e072-0.5*e20*e042+e06*e00*e26+0.5*e20*e062+e03*e00*e23+0.5*e20*e022+1.5*e20*e002+0.5*e20*e032+0.5*e20*e012; a[0 + 10*5]=-e10*e24*e04-e10*e27*e07-e10*e25*e05-e10*e28*e08-e20*e14*e04-e20*e17*e07-e20*e15*e05-e20*e18*e08-e00*e24*e14-e00*e25*e15-e00*e27*e17-e00*e28*e18+e06*e21*e17+e06*e22*e18+e06*e12*e28+e16*e00*e26+e16*e21*e07+e16*e01*e27+e16*e22*e08+e16*e02*e28+e26*e11*e07+e26*e01*e17+e26*e12*e08+e26*e02*e18+e06*e11*e27+e23*e11*e04+e23*e01*e14+e23*e12*e05+e23*e02*e15+e06*e20*e16+e06*e10*e26+e03*e21*e14+e03*e22*e15+e03*e12*e25+e13*e00*e23+e13*e21*e04+e13*e01*e24+e13*e22*e05+e13*e02*e25+e03*e11*e24+e03*e20*e13+e03*e10*e23+e00*e21*e11+3*e00*e20*e10+e00*e22*e12+e20*e12*e02+e20*e11*e01+e10*e22*e02+e10*e21*e01; a[0 + 10*6]=-0.5*e20*e152+e26*e11*e17-e10*e24*e14-e10*e25*e15-e10*e27*e17-e10*e28*e18+0.5*e20*e162+e13*e10*e23+e13*e22*e15+e23*e12*e15+e23*e11*e14+e16*e10*e26+e16*e21*e17+e16*e11*e27+e16*e22*e18+e16*e12*e28+e26*e12*e18+e13*e12*e25+0.5*e20*e132+1.5*e20*e102+0.5*e20*e122+0.5*e20*e112+e10*e21*e11+e10*e22*e12+e13*e11*e24-0.5*e20*e172-0.5*e20*e182-0.5*e20*e142+e13*e21*e14; a[0 + 10*7]=-e20*e25*e05-e20*e28*e08-0.5*e00*e272-0.5*e00*e282-0.5*e00*e242+0.5*e00*e262-0.5*e00*e252+e06*e20*e26+0.5*e00*e232+e06*e22*e28+e06*e21*e27+e26*e21*e07+e26*e01*e27+e26*e22*e08+e26*e02*e28-e20*e24*e04-e20*e27*e07+e03*e20*e23+e03*e22*e25+e03*e21*e24+e23*e21*e04+e23*e01*e24+e23*e22*e05+e23*e02*e25+e20*e21*e01+e20*e22*e02+1.5*e00*e202+0.5*e00*e222+0.5*e00*e212; a[0 + 10*8]=e23*e21*e14+e23*e11*e24+e23*e22*e15+e23*e12*e25+e16*e20*e26+e16*e22*e28+e16*e21*e27+e26*e21*e17+e26*e11*e27+e26*e22*e18+e26*e12*e28+1.5*e10*e202+0.5*e10*e222+0.5*e10*e212+0.5*e10*e232+e20*e21*e11+e20*e22*e12+e13*e20*e23+e13*e22*e25+e13*e21*e24-e20*e24*e14-e20*e25*e15-e20*e27*e17-e20*e28*e18-0.5*e10*e272-0.5*e10*e282-0.5*e10*e242-0.5*e10*e252+0.5*e10*e262; a[0 + 10*9]=0.5*e203+0.5*e20*e222+0.5*e20*e212+0.5*e20*e232+e23*e22*e25+e23*e21*e24+0.5*e20*e262+e26*e22*e28+e26*e21*e27-0.5*e20*e252-0.5*e20*e272-0.5*e20*e282-0.5*e20*e242; a[0 + 10*10]=e06*e32*e08-0.5*e30*e082-0.5*e30*e042-0.5*e30*e052-0.5*e30*e072+0.5*e30*e012+0.5*e30*e022+0.5*e30*e032+0.5*e30*e062+1.5*e30*e002+e00*e31*e01+e00*e32*e02+e03*e31*e04+e03*e01*e34+e03*e32*e05+e03*e02*e35+e33*e01*e04+e33*e02*e05+e06*e00*e36+e06*e31*e07+e06*e01*e37+e06*e02*e38+e36*e01*e07+e36*e02*e08-e00*e34*e04-e00*e37*e07-e00*e35*e05-e00*e38*e08+e03*e00*e33; a[0 + 10*11]=e06*e30*e16+e03*e30*e13+e16*e31*e07+e06*e10*e36-e10*e37*e07+3*e00*e30*e10+e00*e32*e12-e00*e38*e18-e10*e34*e04-e10*e35*e05-e10*e38*e08-e30*e14*e04-e30*e17*e07-e30*e15*e05-e30*e18*e08+e00*e31*e11+e10*e31*e01+e10*e32*e02+e30*e11*e01+e30*e12*e02+e03*e10*e33-e00*e34*e14-e00*e35*e15-e00*e37*e17+e03*e31*e14+e03*e11*e34+e03*e32*e15+e03*e12*e35+e13*e00*e33+e13*e31*e04+e13*e01*e34+e13*e32*e05+e13*e02*e35+e33*e11*e04+e33*e01*e14+e33*e12*e05+e33*e02*e15+e06*e31*e17+e06*e11*e37+e06*e32*e18+e06*e12*e38+e16*e00*e36+e16*e01*e37+e16*e32*e08+e16*e02*e38+e36*e11*e07+e36*e01*e17+e36*e12*e08+e36*e02*e18; a[0 + 10*12]=e13*e10*e33+e33*e11*e14+e16*e10*e36+e16*e31*e17+e16*e11*e37+e16*e32*e18+e16*e12*e38+e36*e12*e18+e36*e11*e17-e10*e34*e14-e10*e35*e15-e10*e37*e17-e10*e38*e18+e10*e31*e11+e10*e32*e12+e13*e31*e14+e13*e11*e34+e13*e32*e15+e13*e12*e35+e33*e12*e15+1.5*e30*e102+0.5*e30*e122+0.5*e30*e112+0.5*e30*e132+0.5*e30*e162-0.5*e30*e152-0.5*e30*e172-0.5*e30*e182-0.5*e30*e142; a[0 + 10*13]=e00*e32*e22+3*e00*e30*e20+e00*e31*e21+e20*e31*e01+e20*e32*e02+e30*e21*e01+e30*e22*e02+e03*e20*e33+e03*e32*e25+e03*e22*e35+e03*e31*e24+e03*e21*e34+e23*e00*e33+e23*e31*e04+e23*e01*e34+e23*e32*e05+e23*e02*e35+e33*e21*e04+e33*e01*e24+e33*e22*e05+e33*e02*e25+e06*e30*e26+e06*e20*e36+e06*e32*e28+e06*e22*e38+e06*e31*e27+e06*e21*e37+e26*e00*e36+e26*e31*e07+e03*e30*e23+e26*e01*e37+e26*e32*e08+e26*e02*e38+e36*e21*e07+e36*e01*e27+e36*e22*e08+e36*e02*e28-e00*e35*e25-e00*e37*e27-e00*e38*e28-e00*e34*e24-e20*e34*e04-e20*e37*e07-e20*e35*e05-e20*e38*e08-e30*e24*e04-e30*e27*e07-e30*e25*e05-e30*e28*e08; a[0 + 10*14]=e16*e30*e26+e13*e21*e34+3*e10*e30*e20+e10*e32*e22+e10*e31*e21+e20*e31*e11+e20*e32*e12+e30*e21*e11+e30*e22*e12+e13*e30*e23+e13*e20*e33+e13*e32*e25+e13*e22*e35+e13*e31*e24+e23*e10*e33+e23*e31*e14+e23*e11*e34+e23*e32*e15+e23*e12*e35+e33*e21*e14+e33*e11*e24+e33*e22*e15+e33*e12*e25+e16*e20*e36+e16*e32*e28+e16*e22*e38+e16*e31*e27+e16*e21*e37+e26*e10*e36+e26*e31*e17+e26*e11*e37+e26*e32*e18+e26*e12*e38+e36*e21*e17+e36*e11*e27+e36*e22*e18+e36*e12*e28-e10*e35*e25-e10*e37*e27-e10*e38*e28-e10*e34*e24-e20*e34*e14-e20*e35*e15-e20*e37*e17-e20*e38*e18-e30*e24*e14-e30*e25*e15-e30*e27*e17-e30*e28*e18; a[0 + 10*15]=-e20*e34*e24+0.5*e30*e262-0.5*e30*e252-0.5*e30*e272-0.5*e30*e282-0.5*e30*e242+1.5*e30*e202+0.5*e30*e222+0.5*e30*e212+0.5*e30*e232+e20*e32*e22+e20*e31*e21+e23*e20*e33+e23*e32*e25+e23*e22*e35+e23*e31*e24+e23*e21*e34+e33*e22*e25+e33*e21*e24+e26*e20*e36+e26*e32*e28+e26*e22*e38+e26*e31*e27+e26*e21*e37+e36*e22*e28+e36*e21*e27-e20*e35*e25-e20*e37*e27-e20*e38*e28; a[0 + 10*16]=0.5*e00*e322+e30*e32*e02+e30*e31*e01+1.5*e00*e302+0.5*e00*e312+e03*e32*e35+e33*e31*e04+e33*e01*e34+e33*e32*e05+e33*e02*e35+e06*e30*e36+e06*e31*e37+e06*e32*e38+e36*e31*e07+e36*e01*e37+e36*e32*e08+e36*e02*e38-e30*e34*e04-e30*e37*e07-e30*e35*e05-e30*e38*e08+0.5*e00*e332+0.5*e00*e362-0.5*e00*e382-0.5*e00*e352-0.5*e00*e342-0.5*e00*e372+e03*e30*e33+e03*e31*e34; a[0 + 10*17]=0.5*e10*e362-0.5*e10*e382-0.5*e10*e352-0.5*e10*e342-0.5*e10*e372+e36*e31*e17+e36*e11*e37+e36*e32*e18+e36*e12*e38-e30*e34*e14-e30*e35*e15-e30*e37*e17-e30*e38*e18+1.5*e10*e302+0.5*e10*e312+0.5*e10*e322+0.5*e10*e332+e30*e31*e11+e30*e32*e12+e13*e30*e33+e13*e31*e34+e13*e32*e35+e33*e31*e14+e33*e11*e34+e33*e32*e15+e33*e12*e35+e16*e30*e36+e16*e31*e37+e16*e32*e38; a[0 + 10*18]=e33*e31*e24+e33*e21*e34+e26*e30*e36+e26*e31*e37+e26*e32*e38+e36*e32*e28+e36*e22*e38+e36*e31*e27+e36*e21*e37-e30*e35*e25-e30*e37*e27-e30*e38*e28-e30*e34*e24+e33*e22*e35+1.5*e20*e302+0.5*e20*e312+0.5*e20*e322+0.5*e20*e332+0.5*e20*e362-0.5*e20*e382-0.5*e20*e352-0.5*e20*e342-0.5*e20*e372+e30*e32*e22+e30*e31*e21+e23*e30*e33+e23*e31*e34+e23*e32*e35+e33*e32*e25; a[0 + 10*19]=0.5*e303+0.5*e30*e312+0.5*e30*e322+0.5*e30*e332+e33*e31*e34+e33*e32*e35+0.5*e30*e362+e36*e31*e37+e36*e32*e38-0.5*e30*e382-0.5*e30*e352-0.5*e30*e342-0.5*e30*e372; a[1 + 10*0]=e00*e01*e04+0.5*e002*e03+e00*e02*e05+0.5*e033+0.5*e03*e042+0.5*e03*e052+0.5*e03*e062+e06*e04*e07+e06*e05*e08-0.5*e03*e012-0.5*e03*e072-0.5*e03*e022-0.5*e03*e082; a[1 + 10*1]=e03*e14*e04+e10*e01*e04+e16*e05*e08+e00*e10*e03+e00*e11*e04+e00*e01*e14+e00*e12*e05+e00*e02*e15+e10*e02*e05+e03*e15*e05+e06*e03*e16+e06*e14*e07+e06*e04*e17+e06*e15*e08+e06*e05*e18+0.5*e002*e13+1.5*e13*e032+0.5*e13*e042+0.5*e13*e052+0.5*e13*e062-0.5*e13*e012-0.5*e13*e072-0.5*e13*e022-0.5*e13*e082+e16*e04*e07-e03*e12*e02-e03*e11*e01-e03*e17*e07-e03*e18*e08; a[1 + 10*2]=-e13*e11*e01+e00*e10*e13+e00*e12*e15+e00*e11*e14+e10*e11*e04+e10*e01*e14+e10*e12*e05+e10*e02*e15+e13*e14*e04+e13*e15*e05+e06*e13*e16+e06*e15*e18+e06*e14*e17+e16*e14*e07+e16*e04*e17+e16*e15*e08+e16*e05*e18-e13*e12*e02-e13*e17*e07-e13*e18*e08+0.5*e102*e03+1.5*e03*e132+0.5*e03*e152+0.5*e03*e142+0.5*e03*e162-0.5*e03*e112-0.5*e03*e172-0.5*e03*e122-0.5*e03*e182; a[1 + 10*3]=0.5*e102*e13+e10*e11*e14+e10*e12*e15+0.5*e133+0.5*e13*e152+0.5*e13*e142+0.5*e13*e162+e16*e15*e18+e16*e14*e17-0.5*e13*e112-0.5*e13*e122-0.5*e13*e172-0.5*e13*e182; a[1 + 10*4]=-e03*e28*e08-e03*e27*e07-e03*e21*e01-e03*e22*e02+e26*e05*e08+e26*e04*e07+e06*e05*e28+e06*e25*e08+e06*e04*e27+e06*e24*e07+e03*e25*e05+e03*e24*e04+e20*e02*e05+e20*e01*e04+e00*e02*e25+e00*e22*e05+e00*e01*e24+e00*e21*e04+e00*e20*e03-0.5*e23*e072-0.5*e23*e082-0.5*e23*e022-0.5*e23*e012+e06*e03*e26+0.5*e23*e052+0.5*e23*e062+1.5*e23*e032+0.5*e23*e042+0.5*e002*e23; a[1 + 10*5]=e00*e21*e14+e00*e11*e24+e00*e10*e23+e00*e22*e15+e00*e12*e25+e20*e12*e05+e20*e01*e14+e20*e11*e04+e00*e20*e13+e10*e02*e25+e10*e22*e05+e10*e01*e24+e10*e21*e04+e10*e20*e03+e23*e15*e05+e23*e14*e04+e13*e25*e05+e13*e24*e04+e03*e24*e14+e03*e25*e15+3*e03*e23*e13+e20*e02*e15+e16*e03*e26+e06*e14*e27-e23*e18*e08+e06*e24*e17+e06*e15*e28+e06*e25*e18+e06*e13*e26+e06*e23*e16+e26*e04*e17+e26*e14*e07+e16*e05*e28+e16*e25*e08+e16*e04*e27+e16*e24*e07-e03*e22*e12-e03*e21*e11+e26*e05*e18+e26*e15*e08-e03*e27*e17-e03*e28*e18-e13*e22*e02-e13*e28*e08-e13*e27*e07-e13*e21*e01-e23*e17*e07-e23*e11*e01-e23*e12*e02; a[1 + 10*6]=-0.5*e23*e182-0.5*e23*e172-0.5*e23*e112-0.5*e23*e122-e13*e22*e12-e13*e27*e17-e13*e28*e18+e26*e15*e18+e26*e14*e17-e13*e21*e11+e20*e12*e15+e13*e25*e15+e13*e24*e14+e16*e13*e26+e16*e25*e18+e16*e15*e28+e16*e24*e17+e16*e14*e27+1.5*e23*e132+0.5*e23*e152+0.5*e23*e142+0.5*e23*e162+e10*e20*e13+e10*e21*e14+e10*e11*e24+e10*e22*e15+e10*e12*e25+e20*e11*e14+0.5*e102*e23; a[1 + 10*7]=e26*e04*e27+e00*e22*e25-e23*e28*e08+0.5*e03*e262-0.5*e03*e212-0.5*e03*e272-0.5*e03*e222-0.5*e03*e282+e23*e24*e04+e23*e25*e05+0.5*e202*e03+e06*e23*e26+e06*e24*e27+e06*e25*e28+e26*e24*e07+e26*e25*e08+e26*e05*e28-e23*e22*e02-e23*e21*e01-e23*e27*e07+e00*e20*e23+e00*e21*e24+e20*e21*e04+e20*e01*e24+e20*e22*e05+e20*e02*e25+1.5*e03*e232+0.5*e03*e242+0.5*e03*e252; a[1 + 10*8]=e20*e11*e24-0.5*e13*e212-0.5*e13*e272-0.5*e13*e222-0.5*e13*e282-e23*e27*e17-e23*e28*e18+e26*e25*e18+e26*e24*e17+e26*e14*e27-e23*e21*e11-e23*e22*e12+e26*e15*e28+e23*e25*e15+e23*e24*e14+e16*e23*e26+e16*e24*e27+e16*e25*e28+0.5*e13*e262+e20*e21*e14+e20*e22*e15+e20*e12*e25+0.5*e13*e242+0.5*e13*e252+0.5*e202*e13+1.5*e13*e232+e10*e20*e23+e10*e22*e25+e10*e21*e24; a[1 + 10*9]=0.5*e202*e23+e20*e22*e25+e20*e21*e24+0.5*e233+0.5*e23*e242+0.5*e23*e252+0.5*e23*e262+e26*e24*e27+e26*e25*e28-0.5*e23*e212-0.5*e23*e272-0.5*e23*e222-0.5*e23*e282; a[1 + 10*10]=e00*e30*e03+0.5*e33*e062-0.5*e33*e012-0.5*e33*e022-0.5*e33*e072+e03*e35*e05+e06*e03*e36+e06*e34*e07+e06*e04*e37+e06*e35*e08+e06*e05*e38+e36*e04*e07+e36*e05*e08-e03*e32*e02-e03*e31*e01-e03*e37*e07+e00*e31*e04+e00*e01*e34+e00*e32*e05+e00*e02*e35+e30*e01*e04+e30*e02*e05+e03*e34*e04-e03*e38*e08+0.5*e002*e33+1.5*e33*e032+0.5*e33*e042+0.5*e33*e052-0.5*e33*e082; a[1 + 10*11]=e06*e35*e18+e06*e33*e16+e00*e30*e13+e00*e10*e33+e00*e31*e14+e00*e11*e34+e00*e32*e15+e00*e12*e35+e10*e30*e03-e33*e17*e07-e33*e18*e08+e10*e31*e04+e10*e01*e34+e10*e32*e05+e10*e02*e35+e30*e11*e04+e30*e01*e14+e30*e12*e05+e30*e02*e15+3*e03*e33*e13+e03*e35*e15+e03*e34*e14+e13*e34*e04+e13*e35*e05+e33*e14*e04+e33*e15*e05+e06*e13*e36+e06*e15*e38+e06*e34*e17+e06*e14*e37+e16*e03*e36+e16*e34*e07+e16*e04*e37+e16*e35*e08+e16*e05*e38+e36*e14*e07+e36*e04*e17+e36*e15*e08+e36*e05*e18-e03*e31*e11-e03*e32*e12-e03*e37*e17-e03*e38*e18-e13*e32*e02-e13*e31*e01-e13*e37*e07-e13*e38*e08-e33*e12*e02-e33*e11*e01; a[1 + 10*12]=e16*e13*e36+e10*e11*e34+0.5*e33*e152+0.5*e33*e142+0.5*e33*e162-0.5*e33*e112-0.5*e33*e122-0.5*e33*e172-0.5*e33*e182+0.5*e102*e33+1.5*e33*e132+e10*e30*e13+e10*e31*e14+e10*e32*e15+e10*e12*e35+e30*e11*e14+e30*e12*e15+e13*e35*e15+e13*e34*e14+e16*e35*e18+e16*e15*e38+e16*e34*e17+e16*e14*e37+e36*e15*e18+e36*e14*e17-e13*e31*e11-e13*e32*e12-e13*e37*e17-e13*e38*e18; a[1 + 10*13]=e06*e35*e28+e36*e04*e27+e00*e20*e33+e00*e30*e23+3*e03*e33*e23+e03*e34*e24+e03*e35*e25+e23*e34*e04+e23*e35*e05+e33*e24*e04+e33*e25*e05+e06*e33*e26+e06*e23*e36+e06*e34*e27+e06*e24*e37+e06*e25*e38+e26*e03*e36+e26*e34*e07+e26*e04*e37+e26*e35*e08+e26*e05*e38+e36*e24*e07+e36*e25*e08+e36*e05*e28-e03*e31*e21-e03*e37*e27-e03*e32*e22-e03*e38*e28-e23*e32*e02-e23*e31*e01-e23*e37*e07-e23*e38*e08-e33*e22*e02-e33*e21*e01-e33*e27*e07-e33*e28*e08+e00*e32*e25+e00*e22*e35+e00*e31*e24+e00*e21*e34+e20*e30*e03+e20*e31*e04+e20*e01*e34+e20*e32*e05+e20*e02*e35+e30*e21*e04+e30*e01*e24+e30*e22*e05+e30*e02*e25; a[1 + 10*14]=e10*e30*e23+e10*e20*e33+e10*e22*e35+e10*e32*e25+e10*e31*e24+e10*e21*e34+e20*e30*e13+e20*e31*e14+e20*e11*e34+e20*e32*e15+e20*e12*e35+e30*e21*e14+e30*e11*e24+e30*e22*e15+e30*e12*e25+3*e13*e33*e23+e13*e34*e24+e13*e35*e25+e23*e35*e15+e23*e34*e14+e33*e25*e15+e33*e24*e14+e16*e33*e26+e16*e23*e36+e16*e34*e27+e16*e24*e37+e16*e35*e28+e16*e25*e38+e26*e13*e36+e26*e35*e18+e26*e15*e38+e26*e34*e17+e26*e14*e37+e36*e25*e18+e36*e15*e28+e36*e24*e17+e36*e14*e27-e13*e31*e21-e13*e37*e27-e13*e32*e22-e13*e38*e28-e23*e31*e11-e23*e32*e12-e23*e37*e17-e23*e38*e18-e33*e21*e11-e33*e22*e12-e33*e27*e17-e33*e28*e18; a[1 + 10*15]=-0.5*e33*e212-0.5*e33*e272-0.5*e33*e222-0.5*e33*e282+e26*e23*e36+e20*e30*e23+e20*e32*e25+e20*e22*e35+e20*e31*e24+e20*e21*e34+e30*e22*e25+e30*e21*e24+e23*e34*e24+e23*e35*e25+e26*e34*e27+e26*e24*e37+e26*e35*e28+e26*e25*e38+e36*e24*e27+e36*e25*e28-e23*e31*e21-e23*e37*e27-e23*e32*e22-e23*e38*e28+0.5*e202*e33+1.5*e33*e232+0.5*e33*e242+0.5*e33*e252+0.5*e33*e262; a[1 + 10*16]=e33*e35*e05+e30*e32*e05+0.5*e03*e362+0.5*e302*e03+1.5*e03*e332+0.5*e03*e352+0.5*e03*e342+e00*e30*e33+e00*e31*e34+e00*e32*e35+e30*e31*e04+e30*e01*e34+e30*e02*e35+e33*e34*e04+e06*e33*e36+e06*e35*e38+e06*e34*e37+e36*e34*e07+e36*e04*e37+e36*e35*e08+e36*e05*e38-e33*e32*e02-e33*e31*e01-e33*e37*e07-e33*e38*e08-0.5*e03*e322-0.5*e03*e382-0.5*e03*e312-0.5*e03*e372; a[1 + 10*17]=-e33*e31*e11-e33*e32*e12-e33*e38*e18+e30*e11*e34+e30*e32*e15+e30*e12*e35+e33*e35*e15+e33*e34*e14+e16*e33*e36+e16*e35*e38+e16*e34*e37+e36*e35*e18+e36*e15*e38+e36*e34*e17+e36*e14*e37-e33*e37*e17+0.5*e302*e13+1.5*e13*e332+0.5*e13*e352+0.5*e13*e342+0.5*e13*e362-0.5*e13*e322-0.5*e13*e382-0.5*e13*e312-0.5*e13*e372+e10*e30*e33+e10*e31*e34+e10*e32*e35+e30*e31*e14; a[1 + 10*18]=e36*e25*e38+0.5*e302*e23+1.5*e23*e332+0.5*e23*e352+0.5*e23*e342+0.5*e23*e362-0.5*e23*e322-0.5*e23*e382-0.5*e23*e312-0.5*e23*e372+e20*e30*e33+e20*e31*e34+e20*e32*e35+e30*e32*e25+e30*e22*e35+e30*e31*e24+e30*e21*e34+e33*e34*e24+e33*e35*e25+e26*e33*e36+e26*e35*e38+e26*e34*e37+e36*e34*e27+e36*e24*e37+e36*e35*e28-e33*e31*e21-e33*e37*e27-e33*e32*e22-e33*e38*e28; a[1 + 10*19]=0.5*e302*e33+e30*e31*e34+e30*e32*e35+0.5*e333+0.5*e33*e352+0.5*e33*e342+0.5*e33*e362+e36*e35*e38+e36*e34*e37-0.5*e33*e322-0.5*e33*e382-0.5*e33*e312-0.5*e33*e372; a[2 + 10*0]=0.5*e002*e06+e00*e01*e07+e00*e02*e08+0.5*e032*e06+e03*e04*e07+e03*e05*e08+0.5*e063+0.5*e06*e072+0.5*e06*e082-0.5*e06*e012-0.5*e06*e022-0.5*e06*e042-0.5*e06*e052; a[2 + 10*1]=e00*e10*e06+0.5*e002*e16+0.5*e032*e16+1.5*e16*e062+0.5*e16*e072+0.5*e16*e082-0.5*e16*e012-0.5*e16*e022-0.5*e16*e042-0.5*e16*e052+e00*e11*e07+e00*e01*e17+e00*e12*e08+e00*e02*e18+e10*e01*e07+e10*e02*e08+e03*e13*e06+e03*e14*e07+e03*e04*e17+e03*e15*e08+e03*e05*e18+e13*e04*e07+e13*e05*e08+e06*e17*e07+e06*e18*e08-e06*e12*e02-e06*e11*e01-e06*e14*e04-e06*e15*e05; a[2 + 10*2]=e13*e14*e07+0.5*e102*e06+e00*e10*e16+e00*e12*e18+e00*e11*e17+e10*e11*e07+e10*e01*e17+e10*e12*e08+e10*e02*e18+e03*e13*e16+e03*e15*e18+e03*e14*e17+e13*e04*e17+e13*e15*e08+e13*e05*e18+e16*e17*e07+e16*e18*e08-e16*e12*e02-e16*e11*e01-e16*e14*e04-e16*e15*e05+0.5*e132*e06+1.5*e06*e162+0.5*e06*e182+0.5*e06*e172-0.5*e06*e112-0.5*e06*e122-0.5*e06*e142-0.5*e06*e152; a[2 + 10*3]=0.5*e102*e16+e10*e12*e18+e10*e11*e17+0.5*e132*e16+e13*e15*e18+e13*e14*e17+0.5*e163+0.5*e16*e182+0.5*e16*e172-0.5*e16*e112-0.5*e16*e122-0.5*e16*e142-0.5*e16*e152; a[2 + 10*4]=e06*e27*e07+e23*e05*e08+e23*e04*e07+e03*e05*e28+e03*e25*e08+e03*e04*e27+e03*e24*e07+e20*e02*e08+e20*e01*e07+e00*e02*e28+e00*e22*e08+e00*e01*e27+e00*e21*e07+e00*e20*e06-e06*e25*e05-e06*e24*e04-e06*e21*e01-e06*e22*e02+e06*e28*e08-0.5*e26*e042-0.5*e26*e052-0.5*e26*e012-0.5*e26*e022+0.5*e26*e082+0.5*e26*e072+1.5*e26*e062+0.5*e002*e26+e03*e23*e06+0.5*e032*e26; a[2 + 10*5]=e13*e05*e28+e00*e12*e28+e13*e25*e08+e13*e04*e27+e13*e24*e07+e13*e23*e06+e03*e14*e27+e03*e24*e17+e03*e15*e28+e03*e25*e18+e03*e13*e26+e03*e23*e16+e20*e02*e18+e20*e12*e08+e20*e01*e17+e20*e11*e07+e00*e21*e17+e10*e02*e28+e10*e22*e08+e10*e01*e27+e10*e21*e07+e10*e20*e06+e00*e11*e27-e26*e15*e05-e26*e14*e04-e26*e11*e01-e26*e12*e02-e16*e25*e05-e16*e24*e04-e16*e21*e01-e16*e22*e02-e06*e24*e14-e06*e22*e12-e06*e21*e11-e06*e25*e15+e00*e20*e16+e00*e22*e18+e00*e10*e26+e26*e18*e08+e26*e17*e07+e16*e28*e08+e16*e27*e07+e06*e27*e17+e06*e28*e18+3*e06*e26*e16+e23*e05*e18+e23*e15*e08+e23*e04*e17+e23*e14*e07; a[2 + 10*6]=e10*e22*e18+0.5*e26*e182+0.5*e26*e172+e16*e28*e18+e16*e27*e17-e16*e25*e15-e16*e21*e11-e16*e22*e12+1.5*e26*e162+e13*e15*e28+e13*e24*e17+e13*e14*e27+e23*e15*e18+e23*e14*e17+e10*e12*e28+e10*e21*e17+e10*e11*e27+e20*e12*e18+e20*e11*e17+e13*e23*e16+e13*e25*e18+e10*e20*e16+0.5*e102*e26-0.5*e26*e122-0.5*e26*e142-0.5*e26*e152-e16*e24*e14-0.5*e26*e112+0.5*e132*e26; a[2 + 10*7]=-0.5*e06*e212-0.5*e06*e252-0.5*e06*e242+0.5*e06*e272+0.5*e06*e282-0.5*e06*e222+e20*e02*e28+e03*e23*e26+e03*e24*e27+e03*e25*e28+e23*e24*e07+e23*e04*e27+e23*e25*e08+e23*e05*e28+e26*e28*e08-e26*e22*e02-e26*e21*e01-e26*e24*e04-e26*e25*e05+e26*e27*e07+e00*e20*e26+e00*e21*e27+e00*e22*e28+e20*e21*e07+e20*e01*e27+e20*e22*e08+0.5*e202*e06+0.5*e232*e06+1.5*e06*e262; a[2 + 10*8]=-e26*e24*e14-0.5*e16*e212-0.5*e16*e252-0.5*e16*e242-e26*e25*e15-0.5*e16*e222-e26*e21*e11+e26*e28*e18+e26*e27*e17-e26*e22*e12+e23*e15*e28+e23*e24*e17+e23*e14*e27+0.5*e232*e16+1.5*e16*e262+0.5*e16*e272+0.5*e16*e282+e10*e20*e26+e10*e21*e27+e10*e22*e28+e20*e22*e18+e20*e12*e28+e20*e21*e17+e20*e11*e27+e13*e23*e26+e13*e24*e27+e13*e25*e28+e23*e25*e18+0.5*e202*e16; a[2 + 10*9]=0.5*e202*e26+e20*e21*e27+e20*e22*e28+0.5*e232*e26+e23*e24*e27+e23*e25*e28+0.5*e263+0.5*e26*e272+0.5*e26*e282-0.5*e26*e222-0.5*e26*e212-0.5*e26*e252-0.5*e26*e242; a[2 + 10*10]=e03*e34*e07+0.5*e032*e36+1.5*e36*e062+e03*e33*e06+e00*e31*e07+e00*e01*e37+e00*e32*e08+e00*e02*e38+e30*e01*e07+e30*e02*e08+e03*e04*e37+e03*e35*e08+e03*e05*e38+0.5*e002*e36-0.5*e36*e022-0.5*e36*e042-0.5*e36*e052+0.5*e36*e072+0.5*e36*e082-0.5*e36*e012+e33*e04*e07+e33*e05*e08+e06*e37*e07+e06*e38*e08-e06*e32*e02-e06*e31*e01-e06*e34*e04-e06*e35*e05+e00*e30*e06; a[2 + 10*11]=e13*e33*e06+e13*e34*e07+e13*e04*e37+e13*e35*e08+e13*e05*e38+e33*e14*e07+e33*e04*e17+e33*e15*e08+e33*e05*e18+3*e06*e36*e16+e06*e38*e18+e06*e37*e17+e16*e37*e07+e16*e38*e08+e36*e17*e07+e36*e18*e08-e06*e35*e15-e06*e31*e11-e06*e32*e12+e00*e31*e17+e00*e11*e37+e10*e30*e06+e10*e31*e07+e10*e01*e37+e10*e32*e08+e10*e02*e38+e30*e11*e07+e30*e01*e17+e30*e12*e08+e30*e02*e18+e03*e33*e16+e03*e13*e36+e03*e35*e18+e03*e15*e38+e03*e34*e17+e03*e14*e37+e00*e30*e16+e00*e12*e38-e06*e34*e14-e16*e32*e02-e16*e31*e01-e16*e34*e04-e16*e35*e05-e36*e12*e02-e36*e11*e01-e36*e14*e04-e36*e15*e05+e00*e10*e36+e00*e32*e18; a[2 + 10*12]=0.5*e36*e182+0.5*e36*e172-0.5*e36*e112-0.5*e36*e122-0.5*e36*e142-0.5*e36*e152+0.5*e102*e36+0.5*e132*e36+1.5*e36*e162+e10*e30*e16+e10*e32*e18+e10*e12*e38+e10*e31*e17+e10*e11*e37+e30*e12*e18+e30*e11*e17+e13*e33*e16+e13*e35*e18+e13*e15*e38+e13*e34*e17+e13*e14*e37+e33*e15*e18+e33*e14*e17+e16*e38*e18+e16*e37*e17-e16*e35*e15-e16*e31*e11-e16*e32*e12-e16*e34*e14; a[2 + 10*13]=e00*e20*e36+e00*e31*e27+e00*e21*e37+e00*e32*e28+e00*e22*e38+e20*e30*e06+e20*e31*e07+e20*e01*e37+e20*e32*e08+e20*e02*e38+e30*e21*e07+e30*e01*e27+e30*e22*e08+e30*e02*e28+e03*e33*e26+e03*e23*e36+e03*e34*e27+e03*e24*e37+e03*e35*e28-e26*e31*e01-e26*e35*e05-e36*e22*e02-e36*e21*e01-e36*e24*e04-e36*e25*e05-e26*e34*e04+e03*e25*e38+e23*e34*e07+e23*e04*e37+e23*e35*e08+e23*e05*e38+e33*e24*e07+e33*e04*e27+e33*e25*e08+e33*e05*e28+3*e06*e36*e26+e06*e37*e27+e06*e38*e28+e26*e37*e07+e26*e38*e08+e36*e27*e07+e36*e28*e08-e06*e32*e22-e06*e31*e21-e06*e35*e25-e06*e34*e24-e26*e32*e02+e00*e30*e26+e23*e33*e06; a[2 + 10*14]=e10*e30*e26+e10*e20*e36+e10*e31*e27+e10*e21*e37+e10*e32*e28+e10*e22*e38+e20*e30*e16+e20*e32*e18+e20*e12*e38+e20*e31*e17+e20*e11*e37+e30*e22*e18+e30*e12*e28+e30*e21*e17+e30*e11*e27+e13*e33*e26+e13*e23*e36+e13*e34*e27+e13*e24*e37+e13*e35*e28+e13*e25*e38+e23*e33*e16+e23*e35*e18+e23*e15*e38+e23*e34*e17+e23*e14*e37+e33*e25*e18+e33*e15*e28+e33*e24*e17+e33*e14*e27+3*e16*e36*e26+e16*e37*e27+e16*e38*e28+e26*e38*e18+e26*e37*e17+e36*e28*e18+e36*e27*e17-e16*e32*e22-e16*e31*e21-e16*e35*e25-e16*e34*e24-e26*e35*e15-e26*e31*e11-e26*e32*e12-e26*e34*e14-e36*e25*e15-e36*e21*e11-e36*e22*e12-e36*e24*e14; a[2 + 10*15]=e33*e25*e28+e20*e30*e26+e20*e32*e28+e20*e31*e27+e20*e21*e37+e20*e22*e38+e30*e21*e27+e30*e22*e28+e23*e33*e26+e23*e34*e27+e23*e24*e37+e23*e35*e28+e23*e25*e38+e33*e24*e27+e26*e37*e27+e26*e38*e28-e26*e32*e22-e26*e31*e21-e26*e35*e25-e26*e34*e24+0.5*e202*e36+0.5*e232*e36+1.5*e36*e262+0.5*e36*e272+0.5*e36*e282-0.5*e36*e222-0.5*e36*e212-0.5*e36*e252-0.5*e36*e242; a[2 + 10*16]=e00*e30*e36+e00*e32*e38+e00*e31*e37+e30*e31*e07+e30*e01*e37+e30*e32*e08+e30*e02*e38+e03*e33*e36-0.5*e06*e342+e03*e35*e38+e33*e34*e07+e33*e04*e37+e33*e35*e08+e33*e05*e38+e36*e37*e07+e36*e38*e08-e36*e32*e02-e36*e31*e01-e36*e34*e04-e36*e35*e05+e03*e34*e37+0.5*e302*e06+0.5*e332*e06+1.5*e06*e362+0.5*e06*e382+0.5*e06*e372-0.5*e06*e352-0.5*e06*e312-0.5*e06*e322; a[2 + 10*17]=-e36*e35*e15+e10*e30*e36+0.5*e302*e16+0.5*e332*e16+1.5*e16*e362+0.5*e16*e382+0.5*e16*e372-0.5*e16*e352-0.5*e16*e312-0.5*e16*e322-0.5*e16*e342+e10*e32*e38+e10*e31*e37+e30*e32*e18+e30*e12*e38+e30*e31*e17+e30*e11*e37+e13*e33*e36+e13*e35*e38+e13*e34*e37+e33*e35*e18+e33*e15*e38+e33*e34*e17+e33*e14*e37+e36*e38*e18+e36*e37*e17-e36*e31*e11-e36*e32*e12-e36*e34*e14; a[2 + 10*18]=-e36*e35*e25+e30*e32*e28+0.5*e302*e26+0.5*e332*e26+1.5*e26*e362+0.5*e26*e382+0.5*e26*e372-0.5*e26*e352-0.5*e26*e312-0.5*e26*e322-0.5*e26*e342+e20*e30*e36+e20*e32*e38+e20*e31*e37+e30*e31*e27+e30*e21*e37+e30*e22*e38+e23*e33*e36+e23*e35*e38+e23*e34*e37+e33*e34*e27+e33*e24*e37+e33*e35*e28+e33*e25*e38+e36*e37*e27+e36*e38*e28-e36*e32*e22-e36*e31*e21-e36*e34*e24; a[2 + 10*19]=0.5*e302*e36+e30*e32*e38+e30*e31*e37+0.5*e332*e36+e33*e35*e38+e33*e34*e37+0.5*e363+0.5*e36*e382+0.5*e36*e372-0.5*e36*e352-0.5*e36*e312-0.5*e36*e322-0.5*e36*e342;  } 

to call same file visual studio, ommitted:

#include "mex.h" #include <math.h>   void mexfunction(int nlhs, mxarray *plhs[],                  int nrhs, const mxarray *prhs[]) 

and replaced with:

#include <float.h> #include <math.h> void  fivepoint_helper (float *a, float *e) 

where e [9x4] input matrix , a [10*20] output matrix ( work linear indexing of matrices).

the problem same c file called matlab mex file or visual studio c file gives different results output matrix a

what causing difference please?

matlab column-major, while c row-major (so input fivepoint_helper has row-major data organization). assuming ee 9 rows 4 columns have,

e27 = ee[2*9 + 7 ]; // row 7, column 2 ? 

where 9 number of rows, looks ok, only column-major inputs. if using read in row-major data in c (non-mex) version, wrong.

for fix, change of these equations deal row-major input, , make mex version work, transpose input. that's quick fix, add transpose inside mex file version.