That's what I was afraid of, but I am definitely open to
any suggestions.
Your suggestion worked. I was successful converting a perl
array ref to a C array and from that I was able to directly
plot the points on a matlab graph.
Just in case you're curious, here is my code:
sub MLlineplot {
my ($data_ref) = @_;
my ($elsX,$elsY);
# Parse the data_ref
$elsX = @{$data_ref->{x}};
$elsY = @{$data_ref->{y}};
unless ($elsX == $elsY) {
print STDERR "ERROR: Vectors x and y do not match. They must have
the".
" same number of elements.\n\n";
pprint($data_ref);
die;
}
cLinePlot($data_ref->{x},$data_ref->{y},$elsX);
} #end MLplot
/*
* cLinePlot() uses pointplot.m to plot a simple line graph
*
* Arguments:
* SV* x - scalar value pointer to the x values array
* SV* y - scalar value pointer to the y values array
* els - integer number of elements in arrays x and y
*
* Note: Error handling for data and options is done in MLplot()
* found above.
*/
void cLinePlot(SV* x, SV* y, int els) {
int i;
SV* tmpX;
SV* tmpY;
double tmpXN;
double tmpYN;
mxArray * X = NULL;
mxArray * Y = NULL;
AV *arrX = (AV*) SvRV(x);
AV *arrY = (AV*) SvRV(y);
double dataX[els];
double dataY[els];
for (i=0; i < els; i++) {
// pull first element off array
tmpX = av_shift(arrX);
tmpY = av_shift(arrY);
// Convert the SV element to a double
tmpXN = SvNV(tmpX);
tmpYN = SvNV(tmpY);
dataX[i] = tmpXN;
dataY[i] = tmpYN;
//printf("%g\n", dataX[i]);
}
// Bind the data stored in data*[] to X or Y(mxArrays)
mlfAssign(&X, mlfDoubleMatrix(1, els, dataX, 0));
mlfAssign(&Y, mlfDoubleMatrix(1, els, dataY, 0));
libpointplotInitialize(); /* Initialize the library of matlab
M-Functions */
/* Call mlfPointPlot, the compiled version of pointplot.m. */
mlfPointplot(X,Y);
libpointplotTerminate(); /* Terminate the library of matlab
M-functions */
mxDestroyArray(X);
mxDestroyArray(Y);
}
Thanks again...Brady
-----Original Message-----
From: Neil Watkiss [mailto:[EMAIL PROTECTED]]
Sent: Monday, June 10, 2002 2:49 PM
To: bbcannon
Cc: 'Elizabeth Mattijsen'; '[EMAIL PROTECTED]'
Subject: Re: Instantiating arrays with Inline
bbcannon [10/06/02 14:43 -0600]:
> That sounds like a great idea if you know a
> more efficient way of creating an array from this string
> reference than Neil showed with his for loop.
> I'm very new to C, can you show me how to do this?
It seems to me that either way you'll be iterating through thousands of
entries. You might save a bit of overhead not going through an AV*, but I
suggest trying it first. Before using a complicated solution, you might as
well see whether the simple one is good enough. You're already in C, which
is
very fast. Otherwise you're going to be taking a Perl array, using join() to
get a string, then basically splitting it up again from C into a C array. It
strikes me that this solution might be _slower_, since you could avoid the
join() and the split() by just converting the Perl array into a C array
directly.
Later,
Neil
