nx_viz_chord.nx source

1// nx_viz_chord.nx -- the CHORD layer of the sovereign Nishi viz library (the d3-chord equivalent, bits-up). 2// Maps an N x N flow matrix to a circular layout: each group gets an arc proportional to its row-sum; within it, 3// sub-arcs per target; a chord (i,j) connects group i's sub-arc-for-j to group j's sub-arc-for-i. Angles in 4// centi-degrees (0..36000) for integer precision. Render with arcs (groups) + curves (chords). Closes 5// layout-chord. license_tier: ORIGINAL 6import "nx_syscalls.nx" 7const K_MAGIC_36000: i64 = 36000 8 9func vch_rowsum(matrix: *i64, n: i64, i: i64) -> i64 { 10 var s: i64 = 0; var j: i64 = 0 11 while j < n { s = s + matrix[i * n + j]; j = j + 1 } 12 return s 13} 14func vch_total(matrix: *i64, n: i64) -> i64 { 15 var s: i64 = 0; var i: i64 = 0 16 while i < n * n { s = s + matrix[i]; i = i + 1 } 17 return s 18} 19// group arcs in centi-degrees: garc_out[i*2]=start, [i*2+1]=end. returns total. 20func vch_groups(matrix: *i64, n: i64, garc_out: *i64) -> i64 { 21 let total: i64 = vch_total(matrix, n) 22 if total <= 0 { return 0 } 23 var cum: i64 = 0; var i: i64 = 0 24 while i < n { 25 let gs: i64 = vch_rowsum(matrix, n, i) 26 garc_out[i * 2] = (cum * K_MAGIC_36000) / total 27 cum = cum + gs 28 garc_out[i * 2 + 1] = (cum * K_MAGIC_36000) / total 29 i = i + 1 30 } 31 return total 32} 33// midpoint angle (centi-deg) of sub-arc (i,j) within group i's arc. 34func vch_sub_mid(matrix: *i64, n: i64, i: i64, j: i64, garc_out: *i64) -> i64 { 35 let gstart: i64 = garc_out[i * 2] 36 let gspan: i64 = garc_out[i * 2 + 1] - gstart 37 let gs: i64 = vch_rowsum(matrix, n, i) 38 if gs <= 0 { return gstart } 39 var before: i64 = 0; var k: i64 = 0 40 while k < j { before = before + matrix[i * n + k]; k = k + 1 } 41 let mid: i64 = before + matrix[i * n + j] / 2 42 return gstart + (mid * gspan) / gs 43} 44func main() -> i64 { return 0 }