Changeset 1482 in lmdz_wrf for trunk

Timestamp:

Apr 1, 2017, 5:50:24 PM (8 years ago)

Author:

lfita

Message:

Adding:

`crossingpoint_2Dlines': Function to determinant the crossing point between two lines in a plane
`points_2Dline': Function to define a line from a pair of points on a plane

File:

• trunk/tools/generic_tools.py (modified) (3 diffs)

trunk/tools/generic_tools.py

@@ -60 +60 @@
 # color_deg: Function to generate a degradation of colors in rgb base
 # contflow: Function to bring back the increment in j,i grid points according to a trip: (inflow directions)
+# crossingpoint_2Dlines: Function to determinant the crossing point between two lines in a plane
 # curvelocalize_2D: Function to provide the localization a curve in a 2D field of positions via the equivalent
 #   i,j-quads within which the curve lays (-1, no value for the given quad [2x2 points around]) and provide 
@@ -103 +104 @@
 # period_information_360d: Function to provide the information of a given period idate, edate (dates in 
 #  [YYYY][MM][DD][HH][MI][SS] format) in a 360 years calendar
+# points_2Dline: Function to define a line from a pair of points on a plane
+# PolyArea: Function to compute the area of the polygon following 'Shoelace formula'
 # pretty_int: Function to plot nice intervals
 # prime_decomposition: Function to decompose a given number with its multiple prime numbers
 # prime_numbers: Function to find all the prime numbers up to a given value above 17
 # printing_dictionary: Function to print the content of a dictionary
-# PolyArea: Function to compute the area of the polygon following 'Shoelace formula'
 # radius_angle: Function to generate a matrix with the angle at a given point
 # radius_dist: Function to generate a matrix with the distance at a given point
@@ -11456 +11458 @@
     return gribcode
 
+def crossingpoint_2Dlines(line1, line2):
+    """ Function to determinant the crossing point between two lines in a plane
+      line1= [a,b,c] terms of the polynomial representation of line1 ax+by+d
+      line2= [a,b,c] terms of the polynomial representation of line2 ax+by+d
+    >>> crossingpoint_2Dlines(np.array([1,-1,0]), np.array([1,1,-3]))
+    [[ 1.5  1.5]]
+    """
+    fname = 'crossingpoint_2lines'
+
+    if len(line1.shape) != len(line2.shape):
+        print errormsg
+        print '  ' + fname + ': rank difference between lines !!'
+        print '    shape line1:', line1.shape, 'line2:', line2.shape
+        quit(-1)
+
+    #determinant
+    matA = np.array([line1[0:2], line2[0:2]])
+    detA = np.linalg.det(matA)
+
+    # x-det
+    matX = np.array([[-line1[2],-line1[1]], [line2[2],line2[1]]])
+    detX = np.linalg.det(matX)
+
+    # y-det
+    matY = np.array([[line1[0],line1[2]], [-line2[0],-line2[2]]])
+    detY = np.linalg.det(matY)
+
+    #print 'mat A:'
+    #print matA
+    #print 'mat X:'
+    #print matX
+    #print 'mat Y:'
+    #print matY
+
+    #print 'det A:', detA, 'X:', detX, 'Y:', detY
+
+    x = detX / detA
+    y = detY / detA
+
+    return np.array([[x, y]])
+
+#print crossingpoint_2Dlines(np.array([1,-1,0]), np.array([1,1,-3]))
+
+def points_2Dline(pt1, pt2):
+    """ Function to define a line from a pair of points on a plane
+          it returns the terms of the polynomial description of the line ax+by+c=0 [a,b,c]
+      pt1= first point [x,y]
+      pt2= second point [x,y]
+    >>> points_2Dline(np.array([1,1]), np.array([2,2]))
+    [1 -1 0]
+    points_2Dline(np.array([1,2]), np.array([2,1]))
+    [1 1 -3]
+    """
+    fname = 'points_2Dline'
+
+    # minus
+    minuseq = pt1 - pt2
+    b = -minuseq[0]/minuseq[1]
+
+    # plus
+    pluseq = pt1 + pt2  
+    subsb = pluseq[1]*b
+
+    subsa = pluseq[0] + subsb
+
+    c = -subsa/2
+
+    return np.array([1, b, c])
+
+line1 = points_2Dline(np.array([1,1]), np.array([2,2]))
+line2 = points_2Dline(np.array([1,2]), np.array([2,1]))
+
+print crossingpoint_2Dlines(np.array([1,-1,0]), np.array([1,1,-3]))
+
 #quit()