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// 00 01 02 03 ...// 10 11 12 13 ...// 20 21 22 23 ...// 30 31 32 33 ...// .  .  .  .  ...// .  .  .  .  ...// .  .  .  .  ...//// [ A I ]// AA^-1 = I// Inverse is the property of a square matrixif(rows!=cols)return;// Matrix must be 3x3 minimumif(rows<3)return;MatrixRxC A = m;MatrixRxC I(rows, cols);I.identity();Scalar sDeterminant = 1.0f;// Forward pass, triangularize lower matrixfor(int i=0; i<cols-1; ++i) {Scalar pivot = A.e[i][i];for(int j=i+1; j<rows; ++j) {Scalar factor;if(A.e[j][i]<0 && A.e[i][i]<0)factor = -fabsf(A.e[j][i]/pivot);else if(A.e[j][i]<0 && A.e[i][i]>0)factor = fabsf(A.e[j][i]/pivot);else if(A.e[j][i]>0 && A.e[i][i]<0)factor = fabsf(A.e[j][i]/pivot);else if(A.e[j][i]>0 && A.e[i][i]>0)factor = -fabsf(A.e[j][i]/pivot);// Complete operation on entire rowfor(int k=0; k<cols; ++k) {A.e[j][k] = A.e[j][k] + factor*A.e[i][k];I.e[j][k] = I.e[j][k] + factor*I.e[i][k];}}}// Check matrix determinant by reduction to triangular formfor(int i=0; i<rows; ++i) {// Add the elements on the main diagonal to obtain the determinantsDeterminant *= A.e[i][i];}if(sDeterminant==0.0f)return; // Matrix has no inverse// Identity pass, triangularize identity diagonalfor(int i=0; i<cols; ++i) {Scalar divide = 1/A.e[i][i];// Complete operation on entire rowfor(int j=0; j<cols; ++j) {A.e[i][j] = A.e[i][j] * divide;I.e[i][j] = I.e[i][j] * divide;}}// Backward pass, triangularize upper matrixfor(int i=cols-1; i>=1; --i) {Scalar pivot = A.e[i][i];for(int j=i-1; j>=0; --j) {Scalar factor;if(A.e[j][i]<0 && A.e[i][i]<0)factor = -fabsf(A.e[j][i]/pivot);else if(A.e[j][i]<0 && A.e[i][i]>0)factor = fabsf(A.e[j][i]/pivot);else if(A.e[j][i]>0 && A.e[i][i]<0)factor = fabsf(A.e[j][i]/pivot);else if(A.e[j][i]>0 && A.e[i][i]>0)factor = -fabsf(A.e[j][i]/pivot);// Complete operation on entire rowfor(int k=0; k<cols; ++k) {A.e[j][k] = A.e[j][k] + factor*A.e[i][k];I.e[j][k] = I.e[j][k] + factor*I.e[i][k];}}}*this = I;}