Transpose matrix (w\ pointers)
 

Hello,
Okay I'm stumped and can't figure out why this code chunk isn't working properly (works on square matrixs; everything else doesn't work)....

uint8 * imageTranspose( uint8 *im ){
uint8 *im_transpose;
int x, y, org_offset, tran_offset;
int im_size = dims[0] * dims[1];

if ( (im_transpose = malloc(sizeof(uint16) * im_size)) == NULL )
mexErrMsgTxt("trans im malloc failed...\n");

//Transpose
for(x=0;x<dims[0]; x++){
for(y=0;y<dims[1]; y++){
org_offset = x+(y*dims[0]); //So X=X & Y=Y
tran_offset= y-(x*dims[1]); //So X=Y & Y=X
*(im_transpose+tran_offset) = *(im+org_offset);
//mexPrintf("%d\t%d\n",*(im+org_offset),*(im_transpose+tran_offset));
}
}

return im_transpose;
}

At the end of the day I will not be using Matlab and therefore I'm just using it as a prototyping tool. Does anyone have any ideas by chance?

Thanks,
Anthony

Re: Transpose matrix (w\ pointers)
 

I might do a transpose like this.

#include <stdio.h>

#include <stdlib.h>



int **create    (                                size_t rows, size_t cols );

void  destroy   (       int             **array, size_t rows);

int **transpose ( const int *const *const array, size_t rows, size_t cols);

void  print     ( const int *const *const array, size_t rows, size_t cols );



int main(void)

{

   size_t rows = 3, cols = 5;

   int **array = create(rows, cols);

   int **trans = transpose(array, rows, cols);

   print(array, rows, cols);

   print(trans, cols, rows);

   destroy(array, rows);

   destroy(trans, cols);

   return 0;

}



int **create(size_t rows, size_t cols)

{

   size_t r, c;

   int k = 0;

   int **array = malloc(rows * sizeof *array);

   if ( array )

   {

      for ( r = 0; r < rows; ++r )

      {

         array[r] = malloc(cols * sizeof *array[r]);

         if ( !array[r] )

         {

            destroy(array, r - 1);

            return NULL;

         }

         for ( c = 0; c < cols; ++c )

         {

            array[r][c] = k++;

         }

      }

   }

   return array;

}



int **transpose(const int *const *const array, size_t rows, size_t cols)

{

   size_t r, c;

   int **result = malloc(cols * sizeof *result);

   if ( result )

   {

      for ( r = 0; r < cols; ++r )

      {

         result[r] = malloc(rows * sizeof *result[r]);

         if ( !result[r] )

         {

            destroy(result, r - 1);

            return NULL;

         }

         for ( c = 0; c < rows; ++c )

         {

            result[r][c] = array[c][r];

         }

      }

   }

   return result;

}



void destroy(int **array, size_t rows)

{

   size_t r;

   for ( r = 0; r < rows; ++r )

   {

      free(array[r]);

   }

   free(array);

}



void print(const int *const *const array, size_t rows, size_t cols)

{

   size_t r, c;

   for ( r = 0; r < rows; ++r )

   {

      for ( c = 0; c < cols; ++c )

      {

         printf("%2d ", array[r][c]);

      }

      putchar('\n');

   }

   putchar('\n');

}



/* my output

 0  1  2  3  4

 5  6  7  8  9

10 11 12 13 14



 0  5 10

 1  6 11

 2  7 12

 3  8 13

 4  9 14

*/

Re: Transpose matrix (w\ pointers)
 

I like that - that looks good.

Thanks,
Anthony

Re: Transpose matrix (w\ pointers)
 

100% correct matrix Transpose program with out any pointer without any complicity.
-------------------------------------------------------------------

#include<stdio.h>

#include<conio.h>

void main()

{

        int a[10][10],i,j,n,m,save;

        clrscr();

        printf("Enter The Rows And Cloumns And Of The First Matrix:");

        scanf("%d%d",&m,&n);

        printf("\nEnter Elements Of The First Matrix:\n");

        for(i=0;i<m;i++)

        {

                for(j=0;j< n;j++)

                {

                        scanf("%d",&a[i][j]);

                }

        }

        

        printf("The First Matrix Is:\n");

        for(i=0;i<m;i++)

        {

                for(j=0;j<n;j++)

                {

                        printf("%d",a[i][j]); //print the first matrix

                }

                printf("\n");

        }

        for (i = 0; i < 4; i++)

        {

                 for (j = 0; j < 4; j++)

                {

                        save = a[i][j];

                        a[i][j] = a[j][i];

                        a[j][i] = save;

                }

        }

        printf("After inverse of Matrix Is:\n");

        for(i=0;i<m;i++)

        {

                for(j=0;j<n;j++)

                {

                        printf("%d",a[j][i]);

                }

                printf("\n");

        }

        getch();

}

Re: Transpose matrix (w\ pointers)
 

Nice job reviving a 2 year old thread? ;)