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getqexpnextterm

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Purpose

Enumerate the list of terms contained in a quadratic expression.

Synopsis

void *getqexpnextterm(XPRMctx ctx, void *quadctx, mmquad_qexp q, void *prev, XPRMmpvar *v1, XPRMmpvar *v2, double *coeff);

Arguments

ctx	Mosel's execution context
quadctx	Context of mmquad
q	Reference to a quadratic expression
prev	Last value returned by this function. Should be NULL for the first call
v1,v2	Pointers to return the decision variable references for the current term
coeff	Pointer to return the coefficient of the current term

Return value

The value to be used as prev for the next call o NULL when all terms have been returned.

Example

The following displays the terms of a quadratic expression:

void dispqexp(XPRMcontext ctx, mmquad_qexp q)
{
 void *prev;
 XPRMmpvar v1,v2;
 double coeff;
 int nlin,ct;
	
 mq->getqexpstat(ctx, quadctx, q, &nlin, NULL, NULL, NULL);
 ct=0;
 prev=mq->getqexpnextterm(ctx, quadctx, q, NULL, &v1, &v2, &coeff);
 mm->printf(ctx, "%g ", coeff);
 while(prev!=NULL) {
  prev=mq->getqexpnextterm(ctx, quadctx, q, prev, &v1, &v2, &coeff);
  if(ct<nlin) { mm->printf(ctx,"%+g %p", coeff, v2); ct++; } 
  else mm->printf(ctx,"%+g %p * %p", coeff, v1, v2);
 }
 mm->printf(ctx,"\n");
} 

Further information

This function can be called repeatedly to enumerate all terms of a quadratic expression. For the first call, the parameter prev must be NULL and the function returns the constant term of the quadratic expression (for v1 and v2 the value NULL is returned and coeff contains the constant term). For the following calls, the value of prev must be the last value returned by the function. The enumeration is completed when the function returns NULL.
If this function is called repeatedly, after the constant term it returns next all linear terms and then the quadratic terms.

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