slepc-3.18.0 2022-10-01
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# FNRationalSetDenominator

Sets the parameters defining the denominator of the rational function.

### Synopsis

    #include "slepcfn.h"
    PetscErrorCode FNRationalSetDenominator(FN fn,PetscInt nq,PetscScalar *qcoeff)

Logically Collective on fn

### Input Parameters

| fn | - the math function context
| nq | - number of coefficients
| qcoeff | - coefficients (array of scalar values)

### Notes

Let the rational function r(x) = p(x)/q(x), where p(x) and q(x) are polynomials. This function provides the coefficients of the denominator q(x). Hence, q(x) is of degree nq-1. If nq is zero, then the function is assumed to be polynomial, r(x) = p(x).

In polynomials, high order coefficients are stored in the first positions of the array, e.g. to represent x^2-3 use {1,0,-3}.

### See Also

FNRationalSetNumerator(), FNRationalGetDenominator()

### Level

intermediate

### Location

src/sys/classes/fn/impls/rational/fnrational.c

### Examples

src/nep/tutorials/ex42.c.html
src/nep/tutorials/nlevp/loaded_string.c.html
Index of all FN routines
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Index of all manual pages