nmr-learning/src/histogram.js

Learn a database of chemical shift and coupling constants assignments

function histogram(opts) {
  var data = opts.data;
  var binsTemp = opts.bins;
  var i = binsTemp.length;

  var bisector = function (f) {
    return {
      left: function (a, x, lo, hi) {
        if (arguments.length < 3) lo = 0;
        if (arguments.length < 4) hi = a.length;
        while (lo < hi) {
          var mid = lo + hi >>> 1;
          if (f.call(a, a[mid], mid) < x) lo = mid + 1;
          else hi = mid;
        }
        return lo;
      },
      right: function (a, x, lo, hi) {
        if (arguments.length < 3) lo = 0;
        if (arguments.length < 4) hi = a.length;
        while (lo < hi) {
          var mid = lo + hi >>> 1;
          if (x < f.call(a, a[mid], mid)) hi = mid;
          else lo = mid + 1;
        }
        return lo;
      }
    };
  };

  var histBisector = bisector(function (d) {
    return d;
  });
    // var bisectLeft = histBisector.left;
  var bisectRight = histBisector.right;
  var bisect = bisectRight;

  var minimum = function (array, f) {
    let i = -1;
    var n = array.length;
    var a, b;
    if (arguments.length === 1) {
      while (++i < n && !((a = array[i]) != null)) a = undefined;
      while (++i < n) if ((b = array[i]) != null && a > b) a = b;
    } else {
      while (++i < n && !((a = f.call(array, array[i], i)) != null)) a = undefined;
      while (++i < n) if ((b = f.call(array, array[i], i)) != null && a > b) a = b;
    }
    return a;
  };

  var maximum = function (array, f) {
    let i = -1;
    var n = array.length;
    var a, b;
    if (arguments.length === 1) {
      while (++i < n && !((a = array[i]) != null)) a = undefined;
      while (++i < n) if ((b = array[i]) != null && b > a) a = b;
    } else {
      while (++i < n && !((a = f.call(array, array[i], i)) != null)) a = undefined;
      while (++i < n) if ((b = f.call(array, array[i], i)) != null && b > a) a = b;
    }
    return a;
  };

  function histFunctor(v) {
    return typeof v === 'function' ? v : function () {
      return v;
    };
  }

  function binsF(x) {
    if (!arguments.length) return binner;
    binner = typeof x === 'number'
      ? function (range) {
        return histLayoutHistogramBinFixed(range, x);
      }
      : histFunctor(x);
    return histogram;
  }

  function histLayoutHistogramBinSturges(range, values) {
    return histLayoutHistogramBinFixed(range, Math.ceil(Math.log(values.length) / Math.LN2 + 1));
  }

  function histLayoutHistogramBinFixed(range, n) {
    var x = -1;
    var b = +range[0];
    var m = (range[1] - b) / n;
    var f = [];
    while (++x <= n) f[x] = m * x + b;
    return f;
  }

  function histLayoutHistogramRange(values) {
    return [minimum(values), maximum(values)];
  }

  var frequency = true;
  var valuer = Number;
  var ranger = histLayoutHistogramRange;
  var binner = histLayoutHistogramBinSturges;

  binsF(binsTemp);

  var bins = [];
  var values = data.map(valuer, this);
  let range2 = ranger.call(this, values, i);
  var thresholds = binner.call(this, range2, values, i);
  i = -1;
  var n = values.length;
  var m = thresholds.length - 1;
  var k = frequency ? 1 : 1 / n;
  var x, bin;

  while (++i < m) {
    bin = bins[i] = [];
    bin.dx = thresholds[i + 1] - (bin.x = thresholds[i]);
    bin.y = 0;
  }

  if (m > 0) {
    i = -1;
    while (++i < n) {
      x = values[i];
      if (x >= range2[0] && x <= range2[1]) {
        bin = bins[bisect(thresholds, x, 1, m) - 1];
        bin.y += k;
        bin.push(data[i]);
      }
    }
  }

  return bins;
}

module.exports = histogram;