[analyticalproblems] add text_problem

src/pymor/analyticalproblems/text.py

@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+# This file is part of the pyMOR project (http://www.pymor.org).
+# Copyright 2013-2017 pyMOR developers and contributors. All rights reserved.
+# License: BSD 2-Clause License (http://opensource.org/licenses/BSD-2-Clause)
+
+from pymor.analyticalproblems.elliptic import StationaryProblem
+from pymor.core.defaults import defaults
+from pymor.domaindescriptions.basic import RectDomain
+from pymor.functions.basic import ConstantFunction, LincombFunction
+from pymor.functions.bitmap import BitmapFunction
+from pymor.parameters.functionals import ProjectionParameterFunctional
+from pymor.parameters.spaces import CubicParameterSpace
+
+
+@defaults('font_name')
+def text_problem(text='pyMOR', font_name=None):
+    import numpy as np
+    from PIL import Image, ImageDraw, ImageFont
+    from tempfile import NamedTemporaryFile
+
+    font_list = [font_name] if font_name else ['DejaVuSansMono.ttf', 'VeraMono.ttf', 'UbuntuMono-R.ttf', 'Arial.ttf']
+    font = None
+    for filename in font_list:
+        try:
+            font = ImageFont.truetype(filename, 64)  # load some font from file of given size
+        except (OSError, IOError):
+            pass
+    if font is None:
+        raise ValueError('Could not load TrueType font')
+
+    size = font.getsize(text)                             # compute width and height of rendered text
+    size = (size[0] + 20, size[1] + 20)                   # add a border of 10 pixels around the text
+
+    def make_bitmap_function(char_num):                   # we need to genereate a BitmapFunction for each character
+        img = Image.new('L', size)                        # create new Image object of given dimensions
+        d = ImageDraw.Draw(img)                           # create ImageDraw object for the given Image
+
+        # in order to position the character correctly, we first draw all characters from the first
+        # up to the wanted character
+        d.text((10, 10), text[:char_num + 1], font=font, fill=255)
+
+        # next we erase all previous character by drawing a black rectangle
+        if char_num > 0:
+            d.rectangle(((0, 0), (font.getsize(text[:char_num])[0] + 10, size[1])), fill=0, outline=0)
+
+        # open a new temporary file
+        with NamedTemporaryFile(suffix='.png') as f:    # after leaving this 'with' block, the temporary
+                                                        # file is automatically deleted
+            img.save(f, format='png')
+            return BitmapFunction(f.name, bounding_box=[(0, 0), size], range=[0., 1.])
+
+    # create BitmapFunctions for each character
+    dfs = [make_bitmap_function(n) for n in range(len(text))]
+
+    # create an indicator function for the background
+    background = ConstantFunction(1., 2) - LincombFunction(dfs, np.ones(len(dfs)))
+
+    # form the linear combination
+    dfs = [background] + dfs
+    coefficients = [1] + [ProjectionParameterFunctional('diffusion', (len(text),), (i,)) for i in range(len(text))]
+    diffusion = LincombFunction(dfs, coefficients)
+
+    return StationaryProblem(
+        domain=RectDomain(dfs[1].bounding_box, bottom='neumann'),
+        neumann_data=ConstantFunction(-1., 2),
+        diffusion=diffusion,
+        parameter_space=CubicParameterSpace(diffusion.parameter_type, 0.1, 1.)
+    )

src/pymor/basic.py

@@ -24,6 +24,7 @@
 from pymor.analyticalproblems.helmholtz import helmholtz_problem
 from pymor.analyticalproblems.instationary import InstationaryProblem
 from pymor.analyticalproblems.thermalblock import thermal_block_problem
+from pymor.analyticalproblems.text import text_problem
 
 from pymor.core.cache import clear_caches, enable_caching, disable_caching
 from pymor.core.defaults import print_defaults, write_defaults_to_file, load_defaults_from_file, set_defaults

src/pymordemos/thermalblock_simple.py

@@ -9,7 +9,7 @@
   thermalblock_simple.py [options] MODEL ALG SNAPSHOTS RBSIZE TEST
 
 Arguments:
-  MODEL      High-dimensional model (pymor, fenics, ngsolve).
+  MODEL      High-dimensional model (pymor, fenics, ngsolve, pymor-text).
 
   ALG        The model reduction algorithm to use
              (naive, greedy, adaptive_greedy, pod).
@@ -36,6 +36,7 @@
 GRID_INTERVALS = 100    # pyMOR/FEniCS
 FENICS_ORDER = 2
 NGS_ORDER = 4
+TEXT = 'pyMOR'
 
 
 ####################################################################################################
@@ -208,6 +209,17 @@ def discretize_ngsolve():
                                     parameter_space=CubicParameterSpace(op.parameter_type, 0.1, 1.))
 
 
+def discretize_pymor_text():
+
+    # setup analytical problem
+    problem = text_problem(TEXT)
+
+    # discretize using continuous finite elements
+    d, _ = discretize_stationary_cg(problem, diameter=1.)
+
+    return d
+
+
 ####################################################################################################
 # Reduction algorithms                                                                             #
 ####################################################################################################
@@ -288,6 +300,8 @@ def main():
         d = discretize_fenics()
     elif MODEL == 'ngsolve':
         d = discretize_ngsolve()
+    elif MODEL == 'pymor-text':
+        d = discretize_pymor_text()
     else:
         raise NotImplementedError
 

src/pymortests/demos.py

@@ -62,6 +62,7 @@
     ('thermalblock_simple', ['pymor', 'naive', 2, 10, 10]),
     ('thermalblock_simple', ['fenics', 'greedy', 2, 10, 10]),
     ('thermalblock_simple', ['ngsolve', 'greedy', 2, 10, 10]),
+    ('thermalblock_simple', ['pymor-text', 'adaptive_greedy', -1, 3, 3]),
 )
 
 THERMALBLOCK_GUI_ARGS = (