some more uint8 woes...

[Brian Blais]

Hello,

I am still having some problems dealing with uint8 types.  In my
application, I want to be able to pass in either a regular (double)
matrix or a uint8 matrix, copy values from the matrix to another 
(double) matrix but (due to size) not convert the entire original 
matrix.  For example, I want to be able to pass in a large 500x500x300 
matrix, and get smaller pieces on the order of 20x20 out of the larger 
one.  I wrote a simple program to play with some of the uint8 
properties, but get an error I don't understand.  I'm using octave 
version 2.1.64 in Linux.  The simple code below takes in a matrix, 
returns the first value of the matrix as a double Matrix (1x1) value. 
It works for the uint8 case, but breaks with the double case like:

> > a=example_uint8(uint8(20))
here
retval = 20
a = 20
> > a=example_uint8(20)
error: octave_base_value::uint8_array_value(): wrong type argument `scalar'
here
retval = 20
error: evaluating assignment expression near line 28, column 2


any ideas?  am I doing something stupid here?  naturally, I will scale
this example up for my application, but this is the simplest example
which reproduces the error.


                        thanks,

                                Brian Blais


#include <octave/oct.h>

DEFUN_DLD (example_uint8, args, nargout,
           "example_uint8.") {

  octave_value_list retval; // #1

  uint8NDArray uint8_m = args(0).uint8_array_value ();
  int is_uint8=(!error_state);

  NDArray double_m;

  if (!is_uint8) {
    double_m= args(0).array_value();
  }

  Matrix ret_mat(1,1,0.0);

  if (is_uint8) {
    ret_mat(0)=(double) uint8_m(0);
  } else  {
    ret_mat(0)=double_m(0);

  }
  retval.append(ret_mat);

// some debugging printfs
  retval(0).print_with_name(octave_stdout,"retval");
  printf("here\n"); fflush(stdout);

  return(retval);
}


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-----------------

            address@hidden
            http://web.bryant.edu/~bblais



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