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unorthodox usage


From: Jonathan Murphy
Subject: unorthodox usage
Date: Wed, 21 Dec 2005 14:54:42 -0500
User-agent: Mozilla Thunderbird 1.0.6 (X11/20051214)

Hi folks,

I am trying to use octave to produce matrices for use with Csound scanned synthesis opcodes. For the curious, the relevant documentation can be found here:

http://www.csounds.com/manual/html/SiggenScanTop.html

The opcode loads its data from an ASCII file consisting of a binary string which expresses the connections in a table. For a table which looks like this:

  | 1 | 2 | 3 | 4 |
------------------------
1 | 0 | 1 | 0 | 0 |
------------------------
2 | 0 | 0 | 1 | 0 |
------------------------
3 | 0 | 0 | 0 | 1 |
------------------------
4 | 0 | 0 | 0 | 0 |
------------------------

The file should look like this:

0
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0

I don't need octave to actually save the file, just print the string to stdout, presumably disp is the best way to do this. I came across a toolbox here:

http://mathphys.physics.kth.se/index.html

which will produce amongst other things an approximation of the Cornu spiral.

function  f=fresn(X);
%> Call: fresn(X) = the complex Fresnel function C(X) + i S(X)
%> Input: X is a real vector or matrix %> Output: fresn(X) is complex of the same dimension.
%> For definitions and values of constants, see
%> Mark A. Heald, Math. Comp. 44(170), 459-461 (1985)
%> and HMF Chap 7.
%> This is a rational approximation with limited accuracy!
%>
%> © Goran Lindblad - address@hidden

SX=sign(X); X=abs(X);%
aa=[.0241212,.068324,.2363641,.1945161,1];
bb=[.118247,.356681,.978113,1.875721,2.7570246,2.9355041,2];
cc=[.0433995,.1339259,.3460509,.6460117,.7769507,1];
dd=[.13634704,.4205217,1.0917325,1.9840524,2.7196741,2.5129806,sqrt(2)];
Rx=polyval(cc,X)./polyval(dd,X);
Ax=(polyval(aa,X)./polyval(bb,X) -X.^2)*pi/2;

Cx=.5 - Rx.*sin(Ax);Sx=.5 - Rx.*cos(Ax);

f=SX.*(Cx+i*Sx);

Is there a way to convert the output of this function (or octave functions in general) to the binary ASCII format that the Csound opcodes require?

Thanks in advance,

Jonathan.





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