# Difference between revisions of "Warp"

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{{hatnote|This article details warp travel. For information about sub-warp speeds, see [[Acceleration]].}} | {{hatnote|This article details warp travel. For information about sub-warp speeds, see [[Acceleration]].}} | ||

+ | {{merge|Warp time calculation|Warp}} | ||

'''Warp''' is the primary method of faster-than-light travel utilized by ships in New Eden. Warp travel is limited to transit between locations within the same solar system, and can only be initiated to locations at least 150 km away. The warp exit point is determined when the warp command is given. This is important if you warp to moving objects like fleet members. You also don't exit warp at the exact point but on a 3 km sphere around the point. This means you sometimes land outside of docking range of a station if you warp to it. This is the reason for [[instadock]] bookmarks. | '''Warp''' is the primary method of faster-than-light travel utilized by ships in New Eden. Warp travel is limited to transit between locations within the same solar system, and can only be initiated to locations at least 150 km away. The warp exit point is determined when the warp command is given. This is important if you warp to moving objects like fleet members. You also don't exit warp at the exact point but on a 3 km sphere around the point. This means you sometimes land outside of docking range of a station if you warp to it. This is the reason for [[instadock]] bookmarks. | ||

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Total time in warp is given by: | Total time in warp is given by: | ||

− | <math> | + | :<math>t_{total} = t_{accel} + t_{decel} + t_{cruise}</math> |

==Long warps== | ==Long warps== | ||

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CCP provided formulae for both distance traveled and velocity reached after ''t'' seconds of acceleration. ''d'' is the distance in meters, ''v'' is speed in meters per second, ''k'' is the ship's warp speed (in AU/s) and ''a'' is 149,597,870,700 meters (1 AU). | CCP provided formulae for both distance traveled and velocity reached after ''t'' seconds of acceleration. ''d'' is the distance in meters, ''v'' is speed in meters per second, ''k'' is the ship's warp speed (in AU/s) and ''a'' is 149,597,870,700 meters (1 AU). | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

d & = e^{kt} \\ | d & = e^{kt} \\ | ||

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To calculate distance traveled while accelerating: | To calculate distance traveled while accelerating: | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

d & = e^{kt} \\ | d & = e^{kt} \\ | ||

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The distance covered while accelerating to ''v<sub>warp</sub>'' is: | The distance covered while accelerating to ''v<sub>warp</sub>'' is: | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

d_{accel} & = \frac{v_{warp}}{k} | d_{accel} & = \frac{v_{warp}}{k} | ||

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To calculate the time spent accelerating to warp speed, the equation for ''v'' should be rearranged to be in terms of ''t'', and then solved for the case of ''v'' being equal to the warp speed (in m/s) | To calculate the time spent accelerating to warp speed, the equation for ''v'' should be rearranged to be in terms of ''t'', and then solved for the case of ''v'' being equal to the warp speed (in m/s) | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

v & = k*e^{kt}\\ | v & = k*e^{kt}\\ | ||

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We want to find the time taken to maximum warp: | We want to find the time taken to maximum warp: | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

v_{warp} & = k * a\\ | v_{warp} & = k * a\\ | ||

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</math> | </math> | ||

− | This formula can be simplified further to <math> | + | This formula can be simplified further to <math>\frac{\ln{a}}{k}</math>, although you may choose not to do this for implementation reasons. |

===Deceleration=== | ===Deceleration=== | ||

− | Deceleration is calculated slightly differently. Instead of using ''k'' to calculate distance and velocity, it uses ''j'', which is defined as <math> | + | Deceleration is calculated slightly differently. Instead of using ''k'' to calculate distance and velocity, it uses ''j'', which is defined as <math>\min(\frac{k}{3},2)</math>. A different rate of deceleration is used to prevent ships suddenly transitioning from "many, many AU away" to "on grid and out of warp" more rapidly than other pilots (or the server / client) can keep up with. |

There is a complication with deceleration calculations. Ships do not drop out of warp at 0 m/s. Instead, they drop out of warp at ''s'' m/s, after which normal sub-warp calculations take over. | There is a complication with deceleration calculations. Ships do not drop out of warp at 0 m/s. Instead, they drop out of warp at ''s'' m/s, after which normal sub-warp calculations take over. | ||

− | <math> | + | :<math>s = \min(100, v_{subwarp}/2)</math> |

Where v<sub>subwarp</sub> is the maximum subwarp velocity of the ship; this varies greatly depending on the ship hull and pilot skills. | Where v<sub>subwarp</sub> is the maximum subwarp velocity of the ship; this varies greatly depending on the ship hull and pilot skills. | ||

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This changes the formulae used slightly. Remember that distance travelled is the integral of velocity. | This changes the formulae used slightly. Remember that distance travelled is the integral of velocity. | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

v & = k * e^{jt}\\ | v & = k * e^{jt}\\ | ||

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The distance covered while decelerating from ''v<sub>warp</sub>'' is | The distance covered while decelerating from ''v<sub>warp</sub>'' is | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

d_{decel} & = \frac{v_{warp}}{j} | d_{decel} & = \frac{v_{warp}}{j} | ||

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As with acceleration, time to decelerate from maximum warp velocity is worked out by rearranging the velocity equation. | As with acceleration, time to decelerate from maximum warp velocity is worked out by rearranging the velocity equation. | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

v &= k*e^{jt}\\ | v &= k*e^{jt}\\ | ||

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While the deceleration from ''s'' to 0 was insignificant in terms of distance, it is significant in terms of time. This means that the time to decelerate is calculated as follows: | While the deceleration from ''s'' to 0 was insignificant in terms of distance, it is significant in terms of time. This means that the time to decelerate is calculated as follows: | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

t_{decel} & = t_{decel\_warp} - t_{decel\_s}\\ | t_{decel} & = t_{decel\_warp} - t_{decel\_s}\\ | ||

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The distance covered while cruising is the total warp distance minus any distance covered while accelerating or decelerating. | The distance covered while cruising is the total warp distance minus any distance covered while accelerating or decelerating. | ||

− | <math> | + | :<math>d_{cruise} = d_{total} - d_{accel} - d_{decel}</math> |

For all but the fastest ships, this will be ''d<sub>total</sub> - 4 AU''. | For all but the fastest ships, this will be ''d<sub>total</sub> - 4 AU''. | ||

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Time spent cruising is: | Time spent cruising is: | ||

− | <math> | + | :<math>t_{cruise} = \frac{d_{cruise}}{v_{warp}}</math> |

==Short Warps== | ==Short Warps== | ||

− | The above calculations work as long as some time is spent at maximum warp speed; <math> | + | The above calculations work as long as some time is spent at maximum warp speed; <math>d_{total} \geq d_{accel} + d_{decel}</math>. If the warp is short enough that the ship never reaches top speed, a different set of calculations are needed. |

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

d_{accel} & = \frac{v_{max}}{k}, d_{decel} = \frac{v_{max}}{j}\\ | d_{accel} & = \frac{v_{max}}{k}, d_{decel} = \frac{v_{max}}{j}\\ | ||

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This enables the calculation of new acceleration and deceleration times using the formulae described in the previous sections, but substituting in the new ''v<sub>max</sub>'': | This enables the calculation of new acceleration and deceleration times using the formulae described in the previous sections, but substituting in the new ''v<sub>max</sub>'': | ||

− | <math> | + | :<math> |

\begin{align} | \begin{align} | ||

t_{accel} & = \frac{\ln{(\frac{v_{max}}{k})}}{k}\\ | t_{accel} & = \frac{\ln{(\frac{v_{max}}{k})}}{k}\\ |

## Latest revision as of 11:37, 18 January 2020

*This article details warp travel. For information about sub-warp speeds, see Acceleration.*

**Warp** is the primary method of faster-than-light travel utilized by ships in New Eden. Warp travel is limited to transit between locations within the same solar system, and can only be initiated to locations at least 150 km away. The warp exit point is determined when the warp command is given. This is important if you warp to moving objects like fleet members. You also don't exit warp at the exact point but on a 3 km sphere around the point. This means you sometimes land outside of docking range of a station if you warp to it. This is the reason for instadock bookmarks.

## Contents

## Stages of warp

Warp travel consists of three stages:

- Acceleration
- Cruising
- Deceleration

It is possible to work out how long it should take for a ship to complete **warp** (once it enters warp) based on formulae released by CCP^{[1]}. Calculating the time taken to warp is done by calculating the time spent in each of these phases and adding them together. This requires calculating acceleration and deceleration time first, followed by cruise time. This calculation does not include the time spent entering warp (accelerating to 75% of maximum velocity), or the time spent slowing after regaining control of the ship.

Total time in warp is given by:

- [math]t_{total} = t_{accel} + t_{decel} + t_{cruise}[/math]

## Long warps

A "long warp" is any warp where there is time to reach maximum warp speed before having to start decelerating.

### Acceleration

#### The formulae

CCP provided formulae for both distance traveled and velocity reached after *t* seconds of acceleration. *d* is the distance in meters, *v* is speed in meters per second, *k* is the ship's warp speed (in AU/s) and *a* is 149,597,870,700 meters (1 AU).

- [math] \begin{align} d & = e^{kt} \\ v & = k*e^{kt}\\ v_{warp} & = k * a\\ \end{align} [/math]

- Distance

To calculate distance traveled while accelerating:

- [math] \begin{align} d & = e^{kt} \\ v & = k*e^{kt}\\ & = k*d\\ \therefore d & = \frac{v}{k} \end{align} [/math]

The distance covered while accelerating to *v _{warp}* is:

- [math] \begin{align} d_{accel} & = \frac{v_{warp}}{k} & = \frac{k*a}{k} & = a \end{align} [/math]

This means that every ship covers exactly 1 AU while accelerating to its maximum warp speed.

- Time

To calculate the time spent accelerating to warp speed, the equation for *v* should be rearranged to be in terms of *t*, and then solved for the case of *v* being equal to the warp speed (in m/s)

- [math] \begin{align} v & = k*e^{kt}\\ \frac{v}{k} & = e^{kt}\\ kt & = \ln{(\frac{v}{k})}\\ t & =\frac{\ln{(\frac{v}{k})}}{k}\\ \end{align} [/math]

We want to find the time taken to maximum warp:

- [math] \begin{align} v_{warp} & = k * a\\ t_{accel} & = \frac{\ln{(\frac{v_{warp}}{k})}}{k}\\ \end{align} [/math]

This formula can be simplified further to [math]\frac{\ln{a}}{k}[/math], although you may choose not to do this for implementation reasons.

### Deceleration

Deceleration is calculated slightly differently. Instead of using *k* to calculate distance and velocity, it uses *j*, which is defined as [math]\min(\frac{k}{3},2)[/math]. A different rate of deceleration is used to prevent ships suddenly transitioning from "many, many AU away" to "on grid and out of warp" more rapidly than other pilots (or the server / client) can keep up with.

There is a complication with deceleration calculations. Ships do not drop out of warp at 0 m/s. Instead, they drop out of warp at *s* m/s, after which normal sub-warp calculations take over.

- [math]s = \min(100, v_{subwarp}/2)[/math]

Where v_{subwarp} is the maximum subwarp velocity of the ship; this varies greatly depending on the ship hull and pilot skills.

- Distance

This changes the formulae used slightly. Remember that distance travelled is the integral of velocity.

- [math] \begin{align} v & = k * e^{jt}\\ d & = \int_{0}^{\infty}k*e^{jt}\,dt = \frac{k*e^{jt}}{j}\\ & = \frac{v}{j} \end{align} [/math]

The distance covered while decelerating from *v _{warp}* is

- [math] \begin{align} d_{decel} & = \frac{v_{warp}}{j} = \frac{k*a}{j} \end{align} [/math]

Note that for ships that travel at up to 6 AU/s, *k* / *j* = *k* / (*k*/3) = 3, so these ships cover 3 AU while decelerating. The complication of not stopping warp at 0 can be safely ignored for distance calculations, because the distance that would be covered while decelerating from 100 m/s is insignificant compared to the ~450 billion meters it takes to decelerate from warp speed to warp drop speed.

- Time

As with acceleration, time to decelerate from maximum warp velocity is worked out by rearranging the velocity equation.

- [math] \begin{align} v &= k*e^{jt}\\ \frac{v}{k} & = e ^ {jt}\\ t & = \frac{\ln{(\frac{v}{k})}}{j} \end{align} [/math]

While the deceleration from *s* to 0 was insignificant in terms of distance, it is significant in terms of time. This means that the time to decelerate is calculated as follows:

- [math] \begin{align} t_{decel} & = t_{decel\_warp} - t_{decel\_s}\\ & = \frac{\ln{(\frac{v_{warp}}{k})}}{j} - \frac{\ln{(\frac{s}{k})}}{j}\\ & = \frac{\ln{(\frac{v_{warp}}{k})} - \ln{(\frac{s}{k})}}{j}\\ & = \frac{\ln{v_{warp}} - \ln{k} - \ln{s} + \ln{k}}{j}\\ & = \frac{\ln{v_{warp}} - \ln{s}}{j}\\ & = \frac{\ln{(\frac{v_{warp}}{s})}}{j} \end{align} [/math]

### Cruising

- Distance

The distance covered while cruising is the total warp distance minus any distance covered while accelerating or decelerating.

- [math]d_{cruise} = d_{total} - d_{accel} - d_{decel}[/math]

For all but the fastest ships, this will be *d _{total} - 4 AU*.

- Time

Time spent cruising is:

- [math]t_{cruise} = \frac{d_{cruise}}{v_{warp}}[/math]

## Short Warps

The above calculations work as long as some time is spent at maximum warp speed; [math]d_{total} \geq d_{accel} + d_{decel}[/math]. If the warp is short enough that the ship never reaches top speed, a different set of calculations are needed.

- [math] \begin{align} d_{accel} & = \frac{v_{max}}{k}, d_{decel} = \frac{v_{max}}{j}\\ d_{total} & = d_{accel} + d_{decel} = v_{max}(\frac{1}{k} + \frac{1}{j})\\ v_{max} & = \frac{d_{total}*k*j}{k + j} \end{align} [/math]

This enables the calculation of new acceleration and deceleration times using the formulae described in the previous sections, but substituting in the new *v _{max}*:

- [math] \begin{align} t_{accel} & = \frac{\ln{(\frac{v_{max}}{k})}}{k}\\ t_{decel} & = \frac{\ln{(\frac{v_{max}}{s})}}{j}\\ t_{total} & = t_{accel} + t_{decel} \end{align} [/math]

## Implementation

The following python code is one possible implementation of the above. It attempts to generate the same data as presented by CCP in the forums. It matches with their numbers, except for 50 AU titan warps, which are one second out. Note that the sub warp speed of the ship is fixed at 200 m/s. This is because the CCP-produced tables assume that every ship drops out of warp at 100 m/s^{[2]}. If trying to run calculations for actual ships, this value will need to be replaced with a more appropriate one. The output values are also passed through the ceil() function, as this is what seems to match the rounding mode that CCP used.^{[3]}

import math AU_IN_M=149597870700 def get_distance(dist): if dist > 1e9: return (dist / AU_IN_M, "AU") else: return (dist/1000, "KM") # Warp speed in AU/s, subwarp speed in m/s, distance in m def calculate_time_in_warp(max_warp_speed, max_subwarp_speed, warp_dist): k_accel = max_warp_speed k_decel = min(max_warp_speed / 3, 2) warp_dropout_speed = min(max_subwarp_speed / 2, 100) max_ms_warp_speed = max_warp_speed * AU_IN_M accel_dist = max_ms_warp_speed / k_accel decel_dist = max_ms_warp_speed / k_decel minimum_dist = accel_dist + decel_dist cruise_time = 0 if minimum_dist > warp_dist: max_ms_warp_speed = warp_dist * k_accel * k_decel / (k_accel + k_decel) else: cruise_time = (warp_dist - minimum_dist) / max_ms_warp_speed accel_time = math.log(max_ms_warp_speed / k_accel) / k_accel decel_time = math.log(max_ms_warp_speed / warp_dropout_speed) / k_decel total_time = cruise_time + accel_time + decel_time distance = get_distance(warp_dist) return total_time distances = [150e3, 1e9, AU_IN_M * 1, AU_IN_M * 2, AU_IN_M * 5, AU_IN_M * 10, AU_IN_M * 20, AU_IN_M * 50, AU_IN_M * 100, AU_IN_M * 200] speeds = [1.36, 1.5, 2, 2.2, 2.5, 2.75, 3, 3.3, 4.5, 5, 5.5, 6, 8] result = {} for speed in speeds: for dist in distances: result[(dist, speed)] = calculate_time_in_warp(speed, 200, dist) print("{:9s}".format(""), end="") for speed in speeds: print("{:9.2f}".format(speed), end="") last_dist = 1e999 for x,y in sorted(result.keys()): dist = get_distance(x) if (y < last_dist): print("\n{:7.5n} {:s}".format(dist[0],dist[1]), end="") last_dist = y print("{:9.0f}".format(math.ceil(result[x,y])), end="") print()

### Output

Warp Speed (AU/s) Distance 1.36 1.50 2.00 2.20 2.50 2.75 3.00 3.30 4.50 5.00 5.50 6.00 8.00 150 KM 22 20 16 14 13 12 11 10 8 7 7 6 6 1e+06 KM 48 44 33 30 27 25 23 21 16 14 13 12 11 1 AU 63 57 43 40 35 32 29 27 20 18 17 15 14 2 AU 65 59 45 41 36 33 30 28 21 19 17 16 15 5 AU 67 61 47 43 38 34 32 29 22 19 18 16 15 10 AU 71 65 49 45 40 36 33 30 23 20 19 17 16 20 AU 78 71 54 49 44 40 37 33 25 22 21 19 17 50 AU 100 91 69 63 56 51 47 43 32 28 26 24 21 100 AU 137 125 94 86 76 69 63 58 43 38 35 32 27 200 AU 211 191 144 131 116 105 97 88 65 58 53 49 40