GANTT : action in past

Question

Hi

I do not understand why the two examples below generate two different Gantt (there are just 2 lines with 2 different order).

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EXAMPLE 1

@startuml
Project starts the 14th of June 2021

[lan1] happens 2021-06-25
[lan4] lasts 2 days
[lan5] lasts 2 days

[lan4] -> [lan5]
[lan1] -> [lan4]
@enduml

---------------------------------------------

EXAMPLE 2

@startuml
Project starts the 14th of June 2021

[lan1] happens 2021-06-25
[lan4] lasts 2 days
[lan5] lasts 2 days

[lan1] -> [lan4]
[lan4] -> [lan5]
@enduml

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Is it a bug ?

Best regards

Answer 1

Hello D.,

That is the fact as Gantt diagram are reading on linear, not globally, but quasi line by line...
You must to declare the tasks or milestones on the right (temporal) order...

See similar observations here:

• https://forum.plantuml.net/11691/nasty-bug-in-gantt-chart-milestone-placement
• https://forum.plantuml.net/12077/gantt-diagram-possible-constraint-task-defined-source-file
• https://forum.plantuml.net/12394/influence-layout-display-order-gantt-multiple-dependencies

If that can help,
Regards,
Th.

Comments

Hi,

Thanks for this response.

We need to make change very often in complex gantts, and we would hope that computer will recalculate all times, duration, delays and so on. It is not a job for human, it is a job for computer.

PlantUML is a great tools, and thanks a lot for it, but it is difficult to use Gantt because there is not global calculation.

Best regards,

D.