Implement matrix truncation for latex to enhance the display of large matrices

sympy/printing/latex.py

@@ -166,6 +166,7 @@ class LatexPrinter(Printer):
         "parenthesize_super": True,
         "min": None,
         "max": None,
+        "full_output": False,
         "diff_operator": "d",
         "adjoint_style": "dagger",
     }
@@ -1686,10 +1687,37 @@ def _print_Piecewise(self, expr):
         return tex % r" \\".join(ecpairs)
 
     def _print_matrix_contents(self, expr):
-        lines = []
 
-        for line in range(expr.rows):  # horrible, should be 'rows'
-            lines.append(" & ".join([self._print(i) for i in expr[line, :]]))
+        visible_rows = 10
+        visible_cols = 10
+        compact = not(self._settings['full_output'])
+
+        row_compactify =  compact and expr.rows > visible_rows
+        col_compactify =  compact and expr.cols > visible_cols
+
+        row_bound = visible_rows if compact and row_compactify else expr.rows
+        col_bound = visible_cols if compact and col_compactify else expr.cols
+
+        lines = [[] for _ in range(row_bound)]
+
+        for i in range(row_bound):
+            lines[i] = [self._print(expr[i, j]) for j in range(col_bound)]
+
+            if col_compactify:
+                # horizental dots and add last element in the ith row
+                lines[i][-2:] = [r'\cdots', self._print(expr[i, -1])]
+
+        if row_compactify:
+            last_row = expr[-1, 0:col_bound]
+            lines[-2:] = [r'\vdots'] * col_bound, [self._print(i) for i in last_row]
+
+        if col_compactify:
+            lines[-1][-2:] = [r'\cdots', self._print(expr[-1, -1])]
+
+        if col_compactify and row_compactify:
+            lines[-2][-2] = r'\ddots' # diagonal dots
+
+        lines = [' & '.join(line) for line in lines]
 
         mat_str = self._settings['mat_str']
         if mat_str is None:
@@ -3049,6 +3077,9 @@ def latex(expr, **settings):
     max: Integer or None, optional
         Sets the upper bound for the exponent to print floating point numbers in
         fixed-point format.
+    full_output: boolean, optional
+        ``False``.  If set to False, output is truncated.  Else, the output
+        is printed normally
     diff_operator: string, optional
         String to use for differential operator. Default is ``'d'``, to print in italic
         form. ``'rd'``, ``'td'`` are shortcuts for ``\mathrm{d}`` and ``\text{d}``.

sympy/printing/tests/test_latex.py

@@ -1550,12 +1550,37 @@ def test_latex_Matrix():
     assert latex(M, mat_delim=None, mat_str='bmatrix') == \
         r'\begin{bmatrix}x + 1 & y\\y & x - 1\end{bmatrix}'
 
-    M2 = Matrix(1, 11, range(11))
-    assert latex(M2) == \
-        r'\left[\begin{array}{ccccccccccc}' \
-        r'0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10\end{array}\right]'
-
-
+    #diagonal dots
+    M1 = latex(Matrix(15, 15, lambda i,j : i + j))
+    assert M1 == \
+    r'\left[\begin{array}{ccccccccccccccc}0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & \cdots & 14'\
+    r'\\1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & \cdots & 15'\
+    r'\\2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & \cdots & 16'\
+    r'\\3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & \cdots & 17'\
+    r'\\4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 & \cdots & 18'\
+    r'\\5 & 6 & 7 & 8 & 9 & 10 & 11 & 12 & \cdots & 19'\
+    r'\\6 & 7 & 8 & 9 & 10 & 11 & 12 & 13 & \cdots & 20'\
+    r'\\7 & 8 & 9 & 10 & 11 & 12 & 13 & 14 & \cdots & 21'\
+    r'\\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \vdots & \ddots & \vdots'\
+    r'\\14 & 15 & 16 & 17 & 18 & 19 & 20 & 21 & \cdots & 28\end{array}\right]'
+
+    #horizontal dots only
+    M2 = latex(Matrix(5, 15, lambda i,j : i + j))
+    assert M2 == r'\left[\begin{array}{ccccccccccccccc}'\
+        r'0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & \cdots & '\
+        r'14\\1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & \cdots & '\
+        r'15\\2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & \cdots & '\
+        r'16\\3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & \cdots & '\
+        r'17\\4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 & \cdots & '\
+        r'18\end{array}\right]'
+
+    #vertical dots only
+    M3 = latex(Matrix(15, 5, lambda i,j : i + j))
+    assert M3 == r'\left[\begin{matrix}0 & 1 & 2 & 3 & 4'\
+    r'\\1 & 2 & 3 & 4 & 5\\2 & 3 & 4 & 5 & 6\\3 & 4 & 5 & 6 & 7'\
+    r'\\4 & 5 & 6 & 7 & 8\\5 & 6 & 7 & 8 & 9\\6 & 7 & 8 & 9 & 10'\
+    r'\\7 & 8 & 9 & 10 & 11\\\vdots & \vdots & \vdots & \vdots &'\
+    r' \vdots\\14 & 15 & 16 & 17 & 18\end{matrix}\right]'
 def test_latex_matrix_with_functions():
     t = symbols('t')
     theta1 = symbols('theta1', cls=Function)