Merge pull request #261 from isuruf/latex

Latex printing on jupyter notebooks

Author: bjodah

symengine/__init__.py

@@ -7,7 +7,7 @@
     ImmutableMatrix, ImmutableDenseMatrix, MutableDenseMatrix,
     MatrixBase, Basic, DictBasic, symarray, series, diff, zeros,
     eye, diag, ones, Derivative, Subs, expand, has_symbol,
-    UndefFunction, Function,
+    UndefFunction, Function, latex,
     have_numpy, true, false, Equality, Unequality, GreaterThan,
     LessThan, StrictGreaterThan, StrictLessThan, Eq, Ne, Ge, Le,
     Gt, Lt, And, Or, Not, Nand, Nor, Xor, Xnor, perfect_power, integer_nthroot,
@@ -19,6 +19,7 @@
 )
 from .utilities import var, symbols
 from .functions import *
+from .printing import init_printing
 
 if have_mpfr:
     from .lib.symengine_wrapper import RealMPFR

symengine/lib/symengine.pxd

@@ -1038,3 +1038,6 @@ cdef extern from "<symengine/sets.h>" namespace "SymEngine":
 cdef extern from "<symengine/solve.h>" namespace "SymEngine":
     cdef RCP[const Set] solve(rcp_const_basic &f, RCP[const Symbol] &sym) nogil except +
     cdef RCP[const Set] solve(rcp_const_basic &f, RCP[const Symbol] &sym, RCP[const Set] &domain) nogil except +
+
+cdef extern from "<symengine/latex.h>" namespace "SymEngine":
+    string latex(const Basic &x) nogil except +

symengine/lib/symengine_wrapper.pyx

@@ -774,6 +774,8 @@ cdef list vec_pair_to_list(symengine.vec_pair& vec):
     return result
 
 
+repr_latex=[False]
+
 cdef class Basic(object):
 
     def __str__(self):
@@ -782,6 +784,12 @@ cdef class Basic(object):
     def __repr__(self):
         return self.__str__()
 
+    def _repr_latex_(self):
+        if repr_latex[0]:
+            return "${}$".format(latex(self))
+        else:
+            return None
+
     def __hash__(self):
         return deref(self.thisptr).hash()
 
@@ -4932,6 +4940,9 @@ def cse(exprs):
     symengine.cse(replacements, reduced_exprs, vec)
     return (vec_pair_to_list(replacements), vec_basic_to_list(reduced_exprs))
 
+def latex(expr):
+    cdef Basic expr_ = sympify(expr)
+    return symengine.latex(deref(expr_.thisptr)).decode("utf-8")
 
 cdef _flattened_vec(symengine.vec_basic &vec, exprs):
     cdef Basic b

symengine/printing.py

@@ -1,4 +1,5 @@
 from symengine.lib.symengine_wrapper import ccode, sympify, Basic
+import symengine.lib.symengine_wrapper
 
 class CCodePrinter:
 
@@ -22,3 +23,12 @@ def doprint(self, expr, assign_to=None):
             code_line = '{}[{}] = {};'.format(assign_to, i, element)
             code_lines.append(code_line)
         return '\n'.join(code_lines)
+
+
+def init_printing(pretty_print=True, use_latex=True):
+    if pretty_print:
+        if not use_latex:
+            raise RuntimeError("Only latex is supported for pretty printing")
+        symengine.lib.symengine_wrapper.repr_latex[0] = True
+    else:
+        symengine.lib.symengine_wrapper.repr_latex[0] = False