ios - Matrix multiplication and inverse problems with accelerate framework -

i trying multiply 2 matrices in objective-c. have imported accelerate framework project in xcode, compiles fine. did matrix multiplication on calculator , got correct values, however, when running code, not. how defined matrices..

float matrixa [3][3] = {{-.045, -.141, -.079}, {-.012, -.079, .0578}, {.112, -.011, -.0830}};  float matrixb [3][1] = {{40}, {-61}, {98}}; 

i used mmul function in accelerate framework..

vdsp_mmul(&matrixa[3][3], 1, &matrixb[3][1], 1, &results[3][1], 1, 3, 1, 3); 

the array results created doing following..

float results[3][1]; 

i placed in viewdidload method of empty project nslog results. when multiply matrixa matrixb should following results.. (-1, 10, -3). however, results in nslog show (-0.045, 0.000, 0.000). not correct , don't understand why. understanding function multiply 2 matrices together. not sure doing. inputing incorrectly , hoping me out.

side note: matrixa inverse of matrix. however, can't find in accelerate framework take inverse. did find function called

sgetrf_ 

with lapack don't it. if has help, advice, or tutorial follow appreciate it, been @ 3 days looking thing on internet!!

you passing pointers memory after end of matrices.

fixing (untested code):

vdsp_mmul(&matrixa[0][0], 1, &matrixb[0][0], 1, &results[0][0], 1, 3, 1, 3); 

passing array function in c pass pointer first element of array, in case appears need do. passing pointer piece of memory directly after final array element in matrices, means you'll nonsense results, or crash.