Use hypot method to avoid over/underflow errors

Use hypot instead of manual calculation

examples/GLIsosurface.py

@@ -28,7 +28,7 @@ def psi(i, j, k, offset=(25, 25, 50)):
     x = i-offset[0]
     y = j-offset[1]
     z = k-offset[2]
-    th = np.arctan2(z, np.sqrt(x**2+y**2))
+    th = np.arctan2(z, np.hypot(x, y))
     phi = np.arctan2(y, x)
     r = np.sqrt(x**2 + y**2 + z **2)
     a0 = 1

examples/GLLinePlotItem.py

@@ -30,14 +30,14 @@ gz.translate(0, 0, -10)
 w.addItem(gz)
 
 def fn(x, y):
-    return np.cos((x**2 + y**2)**0.5)
+    return np.cos(np.hypot(x, y))
 
 n = 51
 y = np.linspace(-10,10,n)
 x = np.linspace(-10,10,100)
 for i in range(n):
     yi = np.array([y[i]]*100)
-    d = (x**2 + yi**2)**0.5
+    d = np.hypot(x, yi)
     z = 10 * np.cos(d) / (d+1)
     pts = np.vstack([x,yi,z]).transpose()
     plt = gl.GLLinePlotItem(pos=pts, color=pg.glColor((i,n*1.3)), width=(i+1)/10., antialias=True)

examples/GLVolumeItem.py

@@ -29,17 +29,14 @@ def psi(i, j, k, offset=(50,50,100)):
     x = i-offset[0]
     y = j-offset[1]
     z = k-offset[2]
-    th = np.arctan2(z, (x**2+y**2)**0.5)
+    th = np.arctan2(z, np.hypot(x, y))
     phi = np.arctan2(y, x)
-    r = (x**2 + y**2 + z **2)**0.5
+    r = np.sqrt(x**2 + y**2 + z **2)
     a0 = 2
     #ps = (1./81.) * (2./np.pi)**0.5 * (1./a0)**(3/2) * (6 - r/a0) * (r/a0) * np.exp(-r/(3*a0)) * np.cos(th)
     ps = (1./81.) * 1./(6.*np.pi)**0.5 * (1./a0)**(3/2) * (r/a0)**2 * np.exp(-r/(3*a0)) * (3 * np.cos(th)**2 - 1)
-    
     return ps
 
-    #return ((1./81.) * (1./np.pi)**0.5 * (1./a0)**(3/2) * (r/a0)**2 * (r/a0) * np.exp(-r/(3*a0)) * np.sin(th) * np.cos(th) * np.exp(2 * 1j * phi))**2 
-
 
 data = np.fromfunction(psi, (100,100,200))
 positive = np.log(np.clip(data, 0, data.max())**2)

examples/optics/pyoptic.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-from math import atan2, asin, sin, cos, sqrt, pi
+from math import atan2, asin, sin, cos, sqrt, pi, hypot
 import pyqtgraph as pg
 from pyqtgraph.Qt import QtGui, QtCore
 import numpy as np
@@ -417,7 +417,7 @@ class CircleSurface(pg.GraphicsObject):
             ## find intersection of circle and line (quadratic formula)
             dx = dir[0]
             dy = dir[1]
-            dr = (dx**2 + dy**2) ** 0.5
+            dr = hypot(dx, dy)  # length
             D = p[0] * (p[1]+dy) - (p[0]+dx) * p[1]
             idr2 = 1.0 / dr**2
             disc = r**2 * dr**2 - D**2
@@ -429,7 +429,6 @@ class CircleSurface(pg.GraphicsObject):
             else:
                 sgn = 1
 
-        
             br = self.path.boundingRect()
             x1 = (D*dy + sgn*dx*disc2) * idr2
             y1 = (-D*dx + abs(dy)*disc2) * idr2

pyqtgraph/Point.py

@@ -6,7 +6,7 @@ Distributed under MIT/X11 license. See license.txt for more information.
 """
 
 from .Qt import QtCore
-from math import sin, acos, atan2, inf, pi
+from math import sin, acos, atan2, inf, pi, hypot
 
 def clip(x, mn, mx):
     if x > mx:
@@ -93,25 +93,13 @@ class Point(QtCore.QPointF):
         return self._math_('__pow__', a)
     
     def _math_(self, op, x):
-        #print "point math:", op
-        #try:
-            #fn  = getattr(QtCore.QPointF, op)
-            #pt = fn(self, x)
-            #print fn, pt, self, x
-            #return Point(pt)
-        #except AttributeError:
         x = Point(x)
         return Point(getattr(self[0], op)(x[0]), getattr(self[1], op)(x[1]))
     
     def length(self):
         """Returns the vector length of this Point."""
-        try:
+        return hypot(self[0], self[1])  # length
-            return (self[0]**2 + self[1]**2) ** 0.5
+
-        except OverflowError:
-            try:
-                return self[1] / sin(atan2(self[1], self[0]))
-            except OverflowError:
-                return inf
     
     def norm(self):
         """Returns a vector in the same direction with unit length."""

pyqtgraph/graphicsItems/ArrowItem.py

@@ -1,3 +1,4 @@
+from math import hypot
 from ..Qt import QtGui, QtCore
 from .. import functions as fn
 import numpy as np
@@ -135,7 +136,7 @@ class ArrowItem(QtGui.QGraphicsPathItem):
         pad = 0
         if self.opts['pxMode']:
             br = self.boundingRect()
-            pad += (br.width()**2 + br.height()**2) ** 0.5
+            pad += hypot(br.width(), br.height())
         pen = self.pen()
         if pen.isCosmetic():
             pad += max(1, pen.width()) * 0.7072

pyqtgraph/graphicsItems/GraphicsItem.py

@@ -1,4 +1,5 @@
 import warnings
+from math import hypot
 from collections import OrderedDict
 from functools import reduce
 from ..Qt import QtGui, QtCore, isQObjectAlive
@@ -308,7 +309,7 @@ class GraphicsItem(object):
         v = self.pixelVectors()
         if v == (None, None):
             return None, None
-        return (v[0].x()**2+v[0].y()**2)**0.5, (v[1].x()**2+v[1].y()**2)**0.5
+        return (hypot(v[0].x(), v[0].y()), hypot(v[1].x(), v[1].y()))  # lengths
 
     def pixelWidth(self):
         ## deprecated

pyqtgraph/graphicsItems/ROI.py

@@ -17,7 +17,7 @@ import numpy as np
 #from numpy.linalg import norm
 from ..Point import *
 from ..SRTTransform import SRTTransform
-from math import atan2, cos, sin, pi, sqrt
+from math import atan2, cos, sin, pi, sqrt, hypot
 from .. import functions as fn
 from .GraphicsObject import GraphicsObject
 from .UIGraphicsItem import UIGraphicsItem
@@ -1247,8 +1247,8 @@ class ROI(GraphicsObject):
         vx = img.mapToData(self.mapToItem(img, QtCore.QPointF(1, 0))) - origin
         vy = img.mapToData(self.mapToItem(img, QtCore.QPointF(0, 1))) - origin
         
-        lvx = sqrt(vx.x()**2 + vx.y()**2)
+        lvx = hypot(vx.x(), vx.y())  # length
-        lvy = sqrt(vy.x()**2 + vy.y()**2)
+        lvy = hypot(vy.x(), vy.y())  # length
         ##img.width is number of pixels, not width of item.
         ##need pxWidth and pxHeight instead of pxLen ?
         sx = 1.0 / lvx
@@ -1887,7 +1887,7 @@ class EllipseROI(ROI):
         h = arr.shape[axes[1]]
 
         ## generate an ellipsoidal mask
-        mask = np.fromfunction(lambda x,y: (((x+0.5)/(w/2.)-1)**2+ ((y+0.5)/(h/2.)-1)**2)**0.5 < 1, (w, h))
+        mask = np.fromfunction(lambda x,y: np.hypot(((x+0.5)/(w/2.)-1), ((y+0.5)/(h/2.)-1)) < 1, (w, h))
         
         # reshape to match array axes
         if axes[0] > axes[1]:

pyqtgraph/opengl/items/GLScatterPlotItem.py

@@ -3,7 +3,8 @@ from OpenGL.GL import *
 from OpenGL.arrays import vbo
 from .. GLGraphicsItem import GLGraphicsItem
 from .. import shaders
-from ... import QtGui
+from ...functions import clip_array
+from ...Qt import QtGui
 import numpy as np
 
 __all__ = ['GLScatterPlotItem']
@@ -62,12 +63,11 @@ class GLScatterPlotItem(GLGraphicsItem):
         ## Generate texture for rendering points
         w = 64
         def fn(x,y):
-            r = ((x-(w-1)/2.)**2 + (y-(w-1)/2.)**2) ** 0.5
+            r = np.hypot((x-(w-1)/2.), (y-(w-1)/2.))
-            return 255 * (w/2. - np.clip(r, w/2.-1.0, w/2.))
+            return 255 * (w/2. - clip_array(r, w/2.-1.0, w/2.))
         pData = np.empty((w, w, 4))
         pData[:] = 255
         pData[:,:,3] = np.fromfunction(fn, pData.shape[:2])
-        #print pData.shape, pData.min(), pData.max()
         pData = pData.astype(np.ubyte)
         
         if getattr(self, "pointTexture", None) is None:

pyqtgraph/widgets/JoystickButton.py

@@ -1,4 +1,5 @@
-from ..Qt import QtGui, QtCore
+from math import hypot
+from ..Qt import QtGui, QtCore, mkQApp
 
 
 __all__ = ['JoystickButton']
@@ -41,7 +42,7 @@ class JoystickButton(QtGui.QPushButton):
         
     def setState(self, *xy):
         xy = list(xy)
-        d = (xy[0]**2 + xy[1]**2)**0.5
+        d = hypot(xy[0], xy[1])  # length
         nxy = [0, 0]
         for i in [0,1]:
             if xy[i] == 0:
@@ -84,7 +85,7 @@ class JoystickButton(QtGui.QPushButton):
         
         
 if __name__ == '__main__':
-    app = pg.mkQApp()
+    app = mkQApp()
     w = QtGui.QMainWindow()
     b = JoystickButton()
     w.setCentralWidget(b)