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POArgument of type float **a in a subroutine
 

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  1. POArgument of type float **a in a subroutine
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    <p>I have an argument in my subroutine defined as <code>float **a</code>.<br> How can I pass this to the function for a 2D array?</p> <p>EDIT: I have included the associated subroutine.</p> <pre><code>#include &lt;math.h&gt; #define NRANSI #include "nrutil.h" #define SWAP(a,b) {temp=(a);(a)=(b);(b)=temp;} void gaussj(float **a, int n, float **b, int m) { int *indxc,*indxr,*ipiv; int i,icol,irow,j,k,l,ll; float big,dum,pivinv,temp; indxc=ivector(1,n); indxr=ivector(1,n); ipiv=ivector(1,n); for (j=1;j&lt;=n;j++) ipiv[j]=0; for (i=1;i&lt;=n;i++) { big=0.0; for (j=1;j&lt;=n;j++) if (ipiv[j] != 1) for (k=1;k&lt;=n;k++) { if (ipiv[k] == 0) { if (fabs(a[j][k]) &gt;= big) { big=fabs(a[j][k]); irow=j; icol=k; } } else if (ipiv[k] &gt; 1) nrerror("gaussj: Singular Matrix-1"); } ++(ipiv[icol]); if (irow != icol) { for (l=1;l&lt;=n;l++) SWAP(a[irow][l],a[icol][l]) for (l=1;l&lt;=m;l++) SWAP(b[irow][l],b[icol][l]) } indxr[i]=irow; indxc[i]=icol; if (a[icol][icol] == 0.0) nrerror("gaussj: Singular Matrix-2"); pivinv=1.0/a[icol][icol]; a[icol][icol]=1.0; for (l=1;l&lt;=n;l++) a[icol][l] *= pivinv; for (l=1;l&lt;=m;l++) b[icol][l] *= pivinv; for (ll=1;ll&lt;=n;ll++) if (ll != icol) { dum=a[ll][icol]; a[ll][icol]=0.0; for (l=1;l&lt;=n;l++) a[ll][l] -= a[icol][l]*dum; for (l=1;l&lt;=m;l++) b[ll][l] -= b[icol][l]*dum; } } for (l=n;l&gt;=1;l--) { if (indxr[l] != indxc[l]) for (k=1;k&lt;=n;k++) SWAP(a[k][indxr[l]],a[k][indxc[l]]); } free_ivector(ipiv,1,n); free_ivector(indxr,1,n); free_ivector(indxc,1,n); } #undef SWAP #undef NRANSI /* (C) Copr. 1986-92 Numerical Recipes Software ("&gt;. */ </code></pre>
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      1. POArgument of type float **a in a subroutine
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    1. COYou can't. A pointer-to-pointer is not a 2D array.
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    2. CO@H2CO3 How can I use it? This argument is a part of Gauss-Jordan algorithm for solving linear equations, and I define a 2 by 2 matrix accordingly.
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      1. POArgument of type float **a in a subroutine
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    3. CO**You can't.** If you have a 2D array, then you have to pass it to a function that accepts a 2D array.
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      1. POArgument of type float **a in a subroutine
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