REF: Rename variables and simplify external deps

Rename variables to be more meaningful
Remove cython overrides as no longer required
Restore multiplication by 0.5 to correct scale
Remove unnecessary installation step on travis

Author: bashtage

.travis.yml

@@ -46,7 +46,6 @@ before_install:
 
 install:
   - python setup.py develop
-  - python setup.py install
 
 script:
   - set -e

randomstate/cython_overrides.pxd

@@ -17,11 +17,12 @@ from libc.stdint cimport (uint8_t, uint16_t, uint32_t, uint64_t,
                           int8_t, int16_t, int32_t, int64_t, intptr_t)
 from libc.stdlib cimport malloc, free
 from libc.math cimport sqrt
-from cpython cimport Py_INCREF, PyComplex_FromDoubles
+from cpython cimport Py_INCREF, PyComplex_FromDoubles, PyComplex_RealAsDouble, \
+    PyComplex_ImagAsDouble, PyInt_AsLong, PyFloat_AsDouble
+
 
 import randomstate
 from binomial cimport binomial_t
-from cython_overrides cimport PyFloat_AsDouble, PyInt_AsLong, PyComplex_RealAsDouble, PyComplex_ImagAsDouble
 from randomstate.entropy import random_entropy
 
 np.import_array()
@@ -1810,7 +1811,7 @@ cdef class RandomState:
             raise ValueError("method must be either 'bm' or 'zig'")
         cdef np.ndarray ogamma, orelation, oloc, randoms, v_real, v_imag, rho
         cdef double *randoms_data
-        cdef double fgamma_r, fgamma_i, frelation_r, frelation_i, frho, f_v_real , f_v_imag, \
+        cdef double fgamma_r, fgamma_i, frelation_r, frelation_i, frho, fvar_r , fvar_i, \
             floc_r, floc_i, f_real, f_imag, i_r_scale, r_scale, i_scale, f_rho
         cdef np.npy_intp i, j, n
         cdef np.broadcast it
@@ -1825,19 +1826,19 @@ cdef class RandomState:
             fgamma_r = PyComplex_RealAsDouble(gamma)
             fgamma_i = PyComplex_ImagAsDouble(gamma)
             frelation_r = PyComplex_RealAsDouble(relation)
-            frelation_i = PyComplex_ImagAsDouble(relation)
+            frelation_i = 0.5 * PyComplex_ImagAsDouble(relation)
 
-            f_v_real = fgamma_r + frelation_r
-            f_v_imag = fgamma_r - frelation_r
+            fvar_r = 0.5 * (fgamma_r + frelation_r)
+            fvar_i = 0.5 * (fgamma_r - frelation_r)
             if fgamma_i != 0:
                 raise ValueError('Im(gamma) != 0')
-            if f_v_imag < 0:
+            if fvar_i < 0:
                 raise ValueError('Re(gamma - relation) < 0')
-            if f_v_real < 0:
+            if fvar_r < 0:
                 raise ValueError('Re(gamma + relation) < 0')
             f_rho = 0.0
-            if f_v_imag > 0 and f_v_real > 0:
-                f_rho = frelation_i / sqrt(f_v_imag * f_v_real)
+            if fvar_i > 0 and fvar_r > 0:
+                f_rho = frelation_i / sqrt(fvar_i * fvar_r)
             if f_rho > 1.0 or f_rho < -1.0:
                 raise ValueError('Im(relation) ** 2 > Re(gamma ** 2 - relation** 2)')
 
@@ -1849,16 +1850,16 @@ cdef class RandomState:
                     random_gauss_fill(&self.rng_state, 1, &f_real)
                     random_gauss_fill(&self.rng_state, 1, &f_imag)
 
-                compute_complex(&f_real, &f_imag, floc_r, floc_i, f_v_real, f_v_imag, f_rho)
+                compute_complex(&f_real, &f_imag, floc_r, floc_i, fvar_r, fvar_i, f_rho)
                 return PyComplex_FromDoubles(f_real, f_imag)
 
             randoms = <np.ndarray>np.empty(size, np.complex128)
             randoms_data = <double *>np.PyArray_DATA(randoms)
             n = np.PyArray_SIZE(randoms)
 
             i_r_scale = sqrt(1 - f_rho * f_rho)
-            r_scale = sqrt(0.5 * f_v_real)
-            i_scale = sqrt(0.5 * f_v_imag)
+            r_scale = sqrt(fvar_r)
+            i_scale = sqrt(fvar_i)
             j = 0
             with self.lock, nogil:
                 if method == u'zig':
@@ -1916,10 +1917,10 @@ cdef class RandomState:
             for i in range(n):
                 floc_r= (<double*>np.PyArray_MultiIter_DATA(it, 1))[0]
                 floc_i= (<double*>np.PyArray_MultiIter_DATA(it, 1))[1]
-                f_v_real = (<double*>np.PyArray_MultiIter_DATA(it, 2))[0]
-                f_v_imag = (<double*>np.PyArray_MultiIter_DATA(it, 3))[0]
+                fvar_r = (<double*>np.PyArray_MultiIter_DATA(it, 2))[0]
+                fvar_i = (<double*>np.PyArray_MultiIter_DATA(it, 3))[0]
                 f_rho = (<double*>np.PyArray_MultiIter_DATA(it, 4))[0]
-                compute_complex(&randoms_data[j], &randoms_data[j+1], floc_r, floc_i, f_v_real, f_v_imag, f_rho)
+                compute_complex(&randoms_data[j], &randoms_data[j+1], floc_r, floc_i, fvar_r, fvar_i, f_rho)
                 j += 2
                 np.PyArray_MultiIter_NEXT(it)