fix(readme): add c implementation for @stdlib/stats/base/dists/invgamma/logpdf

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Author: DhruvArvindSingh

lib/node_modules/@stdlib/stats/base/dists/invgamma/logpdf/README.md

@@ -145,6 +145,92 @@ for ( i = 0; i < 10; i++ ) {
 
 <!-- /.examples -->
 
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/stats/base/dists/invgamma/logpdf.h"
+```
+
+#### stdlib_base_dists_invgamma_logpdf( mu, b )
+
+Evaluates the natural logarithm of the probability density function (PDF) for an inverse gamma distribution with shape parameter `alpha` and scale parameter `beta` at a value `x`.
+
+```c
+double out = stdlib_base_dists_invgamma_logpdf( 2.0, 0.5, 1.0 );
+// returns ~-2.112
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **mu**: `[in] double` location parameter.
+-   **b**: `[in] double` rate parameter.
+
+```c
+double stdlib_base_dists_invgamma_logpdf( const double x, const double mu, const double b );
+```
+
+</section>
+<!-- /.usage -->
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+<section class="notes">
+</section>
+<!-- /.notes -->
+<!-- C API usage examples. -->
+<section class="examples">
+### Examples
+```c
+#include "stdlib/stats/base/dists/laplace/logpdf.h"
+#include <stdlib.h>
+#include <stdio.h>
+static double random_uniform( const double min, const double max ) {
+    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
+    return min + ( v*(max-min) );
+}
+int main( void ) {
+    double mu;
+    double b;
+    double x;
+    double y;
+    int i;
+    for ( i = 0; i < 25; i++ ) {
+        mu = random_uniform( -5.0, 5.0 );
+        b = random_uniform( 0.0, 20.0 );
+        x = random_uniform( 0.0, 20.0 );
+        y = stdlib_base_dists_invgamma_logpdf( x, mu, b );
+        printf( "x: %lf, µ: %lf, b: %lf, logpdf(X;x,µ,b): %lf\n", x, mu, b, y );
+    }
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
 <!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
 
 <section class="related">

lib/node_modules/@stdlib/stats/base/dists/invgamma/logpdf/manifest.json

@@ -39,6 +39,9 @@
       "libpath": [],
       "dependencies": [
         "@stdlib/math/base/napi/ternary",
+        "@stdlib/math/base/special/gammaln",
+        "@stdlib/math/base/special/ln",
+        "@stdlib/constants/float64/ninf",
         "@stdlib/math/base/assert/is-nan"
       ]
     },
@@ -54,6 +57,9 @@
       "libraries": [],
       "libpath": [],
       "dependencies": [
+        "@stdlib/math/base/special/gammaln",
+        "@stdlib/math/base/special/ln",
+        "@stdlib/constants/float64/ninf",
         "@stdlib/constants/float64/eps",
         "@stdlib/math/base/assert/is-nan"
       ]
@@ -70,8 +76,10 @@
       "libraries": [],
       "libpath": [],
       "dependencies": [
-        "@stdlib/constants/float64/eps",
         "@stdlib/math/base/special/gammaln",
+        "@stdlib/math/base/special/ln",
+        "@stdlib/constants/float64/ninf",
+        "@stdlib/constants/float64/eps",
         "@stdlib/math/base/assert/is-nan"
       ]
     }

lib/node_modules/@stdlib/stats/base/dists/invgamma/logpdf/src/main.c

@@ -18,6 +18,7 @@
 
 #include "stdlib/stats/base/dists/invgamma/logpdf.h"
 #include "stdlib/math/base/special/gammaln.h"
+#include "stdlib/math/base/assert/is_nan.h"
 #include "stdlib/math/base/special/ln.h"
 #include "stdlib/constants/float64/ninf.h"