code: def alt_blend_value(data, i, j, k):
      """Computes the average value of the three vertices of a triangle in the
      simplex triangulation, where two of the vertices are on the upper
      horizontal."""
  
      keys = alt_triangle_coordinates(i, j, k)
      return blend_value(data, i, j, k, keys=keys)
  
file_path: python-ternary/ternary/heatmapping.py
imports: import functools
  import numpy
  from matplotlib import pyplot
  from .helpers import unzip, normalize, simplex_iterator, permute_point, project_point
  from .colormapping import get_cmap, colormapper, colorbar_hack
label_desc: Use image node_id 2 for calling a global function with example usage: alt_blend_value(data, i, j, k) and returns: blend_value