===== Primitive: Convolution with set of skeleton arcs =====

**Definition**: <m>sum{}{}{f(r)}</m>\\
f(x) is analytical convolution for an arc with Cauchy kernel [McCormack and Sherstyuk 1998]\\
r - distance to a skeleton point

**Call**: hfConvArc(x,center,radius,theta,axis,angle,S,T);

**Parameters**:

x - point coordinates

center - coordinate array for centers of arcs

radius - array of arcs' radii

theta - array of arcs' angles (from positive x-axis counter-clockwise, 360 for full circle)

axis - array of vectors defining axis of rotation for each arc (placed on local xy-plane)

angle - angles of rotation for arcs around axis of rotation

S - array of kernel width control parameters for each arc

T - threshold

**Test file**: [[http://hyperfun.org/convarc.hf|convarc.hf]]