/**
* Positive Volume Index (PVI)
* Accumulates price changes on days when volume increases from the previous day
*/
/**
* Calculate Positive Volume Index
* @param closes Array of closing prices
* @param volumes Array of volume data
* @param initialPVI Initial PVI value (default 1000)
* @returns PositiveVolumeIndexData object
*/
export function calculatePositiveVolumeIndex(closes, volumes, initialPVI = 1000) {
if (closes.length !== volumes.length || closes.length < 2) {
return null;
}
let pvi = initialPVI;
let lastVolume = volumes[0];
// Calculate PVI up to the current period
for (let i = 1; i < closes.length; i++) {
const currentVolume = volumes[i];
const volumeIncreasing = currentVolume > lastVolume;
if (volumeIncreasing) {
const priceChangePercent = ((closes[i] - closes[i - 1]) / closes[i - 1]) * 100;
pvi = pvi + (pvi * priceChangePercent / 100);
}
lastVolume = currentVolume;
}
// Calculate current period data
const currentVolume = volumes[volumes.length - 1];
const previousVolume = volumes[volumes.length - 2];
const volumeIncreasing = currentVolume > previousVolume;
const volumeChange = ((currentVolume - previousVolume) / previousVolume) * 100;
const priceChange = ((closes[closes.length - 1] - closes[closes.length - 2]) / closes[closes.length - 2]) * 100;
// Determine trend based on PVI slope
let trend = 'neutral';
let slope = 0;
if (closes.length >= 5) {
// Calculate slope over last 5 periods
const recentPVI = calculatePVIHistory(closes.slice(-5), volumes.slice(-5), initialPVI);
if (recentPVI.length >= 2) {
slope = (recentPVI[recentPVI.length - 1] - recentPVI[0]) / (recentPVI.length - 1);
if (slope > 1) {
trend = 'bullish';
}
else if (slope < -1) {
trend = 'bearish';
}
}
}
// Calculate signal strength based on slope magnitude
const strength = Math.min(100, Math.abs(slope) * 10);
// Generate trading signal
let signal = 'neutral';
if (volumeIncreasing && trend === 'bullish' && strength > 20) {
signal = 'buy';
}
else if (volumeIncreasing && trend === 'bearish' && strength > 20) {
signal = 'sell';
}
return {
pvi,
volumeChange,
priceChange,
trend,
strength,
slope,
signal,
volumeIncreasing
};
}
/**
* Calculate Negative Volume Index
* @param closes Array of closing prices
* @param volumes Array of volume data
* @param initialNVI Initial NVI value (default 1000)
* @returns NegativeVolumeIndexData object
*/
export function calculateNegativeVolumeIndex(closes, volumes, initialNVI = 1000) {
if (closes.length !== volumes.length || closes.length < 2) {
return null;
}
let nvi = initialNVI;
let lastVolume = volumes[0];
// Calculate NVI up to the current period
for (let i = 1; i < closes.length; i++) {
const currentVolume = volumes[i];
const volumeDecreasing = currentVolume < lastVolume;
if (volumeDecreasing) {
const priceChangePercent = ((closes[i] - closes[i - 1]) / closes[i - 1]) * 100;
nvi = nvi + (nvi * priceChangePercent / 100);
}
lastVolume = currentVolume;
}
// Calculate current period data
const currentVolume = volumes[volumes.length - 1];
const previousVolume = volumes[volumes.length - 2];
const volumeDecreasing = currentVolume < previousVolume;
const volumeChange = ((currentVolume - previousVolume) / previousVolume) * 100;
const priceChange = ((closes[closes.length - 1] - closes[closes.length - 2]) / closes[closes.length - 2]) * 100;
// Determine trend based on NVI slope
let trend = 'neutral';
let slope = 0;
if (closes.length >= 5) {
const recentNVI = calculateNVIHistory(closes.slice(-5), volumes.slice(-5), initialNVI);
if (recentNVI.length >= 2) {
slope = (recentNVI[recentNVI.length - 1] - recentNVI[0]) / (recentNVI.length - 1);
if (slope > 1) {
trend = 'bullish';
}
else if (slope < -1) {
trend = 'bearish';
}
}
}
const strength = Math.min(100, Math.abs(slope) * 10);
let signal = 'neutral';
if (volumeDecreasing && trend === 'bullish' && strength > 20) {
signal = 'buy';
}
else if (volumeDecreasing && trend === 'bearish' && strength > 20) {
signal = 'sell';
}
return {
nvi,
volumeChange,
priceChange,
trend,
strength,
slope,
signal,
volumeDecreasing
};
}
/**
* Helper function to calculate PVI history
*/
function calculatePVIHistory(closes, volumes, initialPVI) {
const pviValues = [];
let pvi = initialPVI;
let lastVolume = volumes[0];
pviValues.push(pvi);
for (let i = 1; i < closes.length; i++) {
const currentVolume = volumes[i];
const volumeIncreasing = currentVolume > lastVolume;
if (volumeIncreasing) {
const priceChangePercent = ((closes[i] - closes[i - 1]) / closes[i - 1]) * 100;
pvi = pvi + (pvi * priceChangePercent / 100);
}
pviValues.push(pvi);
lastVolume = currentVolume;
}
return pviValues;
}
/**
* Helper function to calculate NVI history
*/
function calculateNVIHistory(closes, volumes, initialNVI) {
const nviValues = [];
let nvi = initialNVI;
let lastVolume = volumes[0];
nviValues.push(nvi);
for (let i = 1; i < closes.length; i++) {
const currentVolume = volumes[i];
const volumeDecreasing = currentVolume < lastVolume;
if (volumeDecreasing) {
const priceChangePercent = ((closes[i] - closes[i - 1]) / closes[i - 1]) * 100;
nvi = nvi + (nvi * priceChangePercent / 100);
}
nviValues.push(nvi);
lastVolume = currentVolume;
}
return nviValues;
}
/**
* Get PVI interpretation
* @param pvi PositiveVolumeIndexData object
* @returns Human-readable interpretation
*/
export function getPVIInterpretation(pvi) {
const { trend, volumeIncreasing, strength, signal } = pvi;
let interpretation = `PVI: ${pvi.pvi.toFixed(2)}`;
if (volumeIncreasing) {
interpretation += ' (Volume ↑)';
}
else {
interpretation += ' (Volume ↓)';
}
interpretation += ` - ${trend} trend`;
if (strength > 50) {
interpretation += ' (Strong)';
}
else if (strength > 20) {
interpretation += ' (Moderate)';
}
else {
interpretation += ' (Weak)';
}
if (signal !== 'neutral') {
interpretation += ` - ${signal.toUpperCase()} signal`;
}
return interpretation;
}
/**
* Get NVI interpretation
* @param nvi Negative volume index data
* @returns Human-readable interpretation
*/
export function getNVIInterpretation(nvi) {
const { trend, volumeDecreasing, strength, signal } = nvi;
let interpretation = `NVI: ${nvi.nvi.toFixed(2)}`;
if (volumeDecreasing) {
interpretation += ' (Volume ↓)';
}
else {
interpretation += ' (Volume ↑)';
}
interpretation += ` - ${trend} trend`;
if (strength > 50) {
interpretation += ' (Strong)';
}
else if (strength > 20) {
interpretation += ' (Moderate)';
}
else {
interpretation += ' (Weak)';
}
if (signal !== 'neutral') {
interpretation += ` - ${signal.toUpperCase()} signal`;
}
return interpretation;
}
/**
* Analyze smart money vs public participation
* @param pvi PositiveVolumeIndexData object
* @param nvi Negative volume index data
* @returns Analysis of market participation
*/
export function analyzeSmartMoneyParticipation(pvi, nvi) {
const pviStrength = pvi.strength;
const nviStrength = nvi.strength;
let dominantForce;
let confidence;
let interpretation;
if (nviStrength > pviStrength * 1.5) {
dominantForce = 'smart_money';
confidence = Math.min(100, nviStrength);
interpretation = 'Smart money (institutional investors) are more active on down volume days';
}
else if (pviStrength > nviStrength * 1.5) {
dominantForce = 'public';
confidence = Math.min(100, pviStrength);
interpretation = 'Public participation is higher on up volume days';
}
else {
dominantForce = 'balanced';
confidence = Math.min(100, (pviStrength + nviStrength) / 2);
interpretation = 'Balanced participation between smart money and public';
}
return { dominantForce, confidence, interpretation };
}
