Add ndtri, igam, chdtr

setup.py

@@ -20,5 +20,8 @@
         "pytest",
         "scipy",
     ],
-    cffi_modules=["src/_cffi_src/build_hyper.py:ffi"],
+    cffi_modules=["src/_cffi_src/build_hyper.py:ffi",
+                  "src/_cffi_src/build_ndtri.py:ffi",
+                  "src/_cffi_src/build_igam.py:ffi",
+                  "src/_cffi_src/build_chi2.py:ffi"],
 )

src/_cffi_src/build_chi2.py

@@ -0,0 +1,24 @@
+# Inspired by pyca/cryptography (Apache/BSD)
+
+from cffi import FFI
+
+
+ffi = FFI()
+ffi.cdef("""
+double chdtr( double df, double x );
+double chdtri( double df, double y );
+double chdtrc( double df, double x );
+""")
+ffi.set_source(
+    "_chi2",
+    """
+double chdtr( double df, double x );
+double chdtri( double df, double y );
+double chdtrc( double df, double x );
+""",
+    libraries=["md"],
+)
+
+
+if __name__ == '__main__':
+    ffi.compile()

src/_cffi_src/build_igam.py

@@ -0,0 +1,22 @@
+# Inspired by pyca/cryptography (Apache/BSD)
+
+from cffi import FFI
+
+
+ffi = FFI()
+ffi.cdef("""
+double igam(double s, double x);
+double igamc(double s, double x);
+""")
+ffi.set_source(
+    "_igam",
+    """
+double igam(double s, double x);
+double igamc(double s, double x);
+""",
+    libraries=["md"],
+)
+
+
+if __name__ == '__main__':
+    ffi.compile()

src/_cffi_src/build_ndtri.py

@@ -0,0 +1,20 @@
+# Inspired by pyca/cryptography (Apache/BSD)
+
+from cffi import FFI
+
+
+ffi = FFI()
+ffi.cdef("""
+double ndtri(double y0);
+""")
+ffi.set_source(
+    "_ndtri",
+    """
+double ndtri(double y0);
+""",
+    libraries=["md"],
+)
+
+
+if __name__ == '__main__':
+    ffi.compile()

src/pycephes/chi2.py

@@ -0,0 +1,30 @@
+import numpy as np
+from numba import cffi_support, float32, float64, vectorize
+
+import _chi2
+from _chi2 import lib, ffi
+
+cffi_support.register_module(_chi2)
+_chdtr = lib.chdtr
+_chdtrc = lib.chdtrc
+_chdtri = lib.chdtri
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def cdf(x, df):
+    return _chdtr(df, x)
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def ppf(p, df):
+    return _chdtri(df, 1.0-p)
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def sf(p, df):
+    return _chdtrc(df, p)
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def isf(p, df):
+    return _chdtri(df, p)

src/pycephes/igam.py

@@ -0,0 +1,19 @@
+import numpy as np
+from numba import cffi_support, float32, float64, vectorize
+
+import _igam
+from _igam import lib, ffi
+
+cffi_support.register_module(_igam)
+_igam = lib.igam
+_igamc = lib.igamc
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def lower(s, x):
+    return _igam(s, x)
+
+@vectorize([float64(float64, float64),
+            float32(float32, float32)])
+def upper(s, x):
+    return _igamc(s, x)

src/pycephes/ndtri.py

@@ -0,0 +1,14 @@
+import numpy as np
+from numba import njit, cffi_support
+
+import _ndtri
+from _ndtri import lib, ffi
+
+cffi_support.register_module(_ndtri)
+
+_ndtri = lib.ndtri
+
+
+@njit
+def ndtri(q):
+    return _ndtri(q)